For the general theory of Widmore's involvement with Flight 815 see here.
Who else would know about the kind of boats that could be used in Widmore's race, and afford to give one a way, as well as has a strange interest in Desmond? So far, the only character who could make this extremely unlikely coincidence possible is Widmore, who we know has an interest in both Desmond and the Island.
Extremely unlikely coincidences are rife through the show.
It was Desmond's 'destiny' to go to the island, so he was going to get the boat somehow. It is very likely coincidence that it is from Libby. Also, Widmore couldn't possibly foresee Desmond happening upon the island in the middle of the ocean on his tour around the world.
If she indeed sent Desmond on that boat suspecting what would happen, at Widmore's request, that would explain why she doesn't appear to Hurley after her death ( she's ashamed, feeling guilty ).
The fact that she radically changes her hair color suggests that she might be concealing her identity. When she meets Desmond she has red hair, Hurley - brown, and on Flight 815: blond.
Her medical knowledge (shown when she first arrived with the other survivors) may have been the result not of medical school, but rather that she prepared in advance with first aide training because she knew she was headed to the island.
Also the fact that she starts dating Hurley, never mentioning that she had seen him before, seems like she has some reason for being around him. Hurley himself mentioned how improbable their relationship was given his physique. Maybe she had an ulterior motive. But clearly, given that she helped talk him down from suicide, she was interested in his well-being.
She feels a connection to him because they were both at Santa Rosa, so she knows what he's going through.
Might not have been in the mental hospital for Hurley, but rather Leonard.(if she is working for Widmore and knows about Leonard, the numbers and the island.)
She may have just been in the institution for legitimate reasons.
In the brief scene of her at Santa Rosa, she seems fairly mental.
Many many many character coincidences appear in Lost. (Boone-Sawyer, Anna Lucia-Christian Sheppard, Jack-Desmond, the list goes on), there is nothing at all to suggest that Libby meeting Desmond wasn't another character coincidence.
Widmore wouldn't know that 815 was going to crash.
Widmore would have known 815 was going to crash because he knew the survivors who were jumping through time and used his resources to find the flight that they were all on.
Widmore never got identification for their full names, nor the timeperiod they were from. They merely said future. I don't think he even knew the island was breached via 815 until it disappeared in the South Pacific.
Given that most of the people on the plane died when it crashed it is an unreliable way to get to the island.
And yet when they all want to get back to the island 3 years after leaving they get on a plane intending to crash.
The get on the plane expecting the island wants them back and will take them somehow. They also know for a fact the plane will pass over the temporary location of the island, and Widmore obviously doesn't have access/isn't aware of The Lamp Post station.
Why would Widmore want her on the island?
A clinical psychologist with a direct tie to Desmond would be a valuable asset to have on the island because she would have a few cards to play, such as the Penny card.
Widmore would have gone on the plane himself
He didn't go on the Kahana himself. And why send Libby instead of the freighter field ops (Naomi, Daniel, Charlotte, Miles, and Keamy) if he knew about it before-hand?
Theory 2: Everything she said was true
She was telling the truth about almost everything. She was an American psychologist working in Australia, married to her husband who died. Afterwards, she had a nervous breakdown in L.A.. She did not come to Australia for Hurley. She is not an Other. She is not a pathological liar. She is not a fiendish manipulator. If she recognizes Hurley from Santa Rosa she refuses to mention it because she is ashamed of being in a mental hospital.
She seemed to be taking medicine at Santa Rosa.
She seemed very distraught and depressed, like most other patients at Santa Rosa.
Nothing at all to suggest she was lying.
She had feelings for Hurley because they both share a connection of being mentally unstable.
Who gives a boat to a stranger?
A person who has no interest in boats
A romantic altruist
A person recovering from a history of depression and/or mental illness
A person who had been told to
A person written into a story riddled with coincidences
She had to be lying about Hurley stepping on her foot, she was in the tail section, he was in the middle...he would of never passed her.
Unless he had gone to the rear of the plane to use the restroom or ask something of the flight attendants.
taken from transcript: LIBBY: "Yes, you did. And it was hard. I know that because I remember you were the last one on the flight, and you were all sweaty, and you had headphones on -- and crunch. You stepped on my foot...." so it was right when he got on the plane that she is referring too.
Libby was originally seated in the middle of the plane because in a deleted scene she tells Claire that she is wearing her shirt. If Libby had her luggage in the tail section Claire couldn't be wearing her shirt. Libby probably wanted to sit in the back of the plane.
She is lying to give Hurley an explanation as to why he recognizes her so that he won't remember her at Santa Rosa.
What if there were some people sent to fly on Oceanic 815 in order to subtly manipulate events? There's a lot up in the air at this point....
There is indeed. It seemed that Cindy (the flight attendant) assimilated a little too quickly and easily into the "Others". She was also responsible for giving Jack a juice-like drink (remember Juliet's juice?) right before the crash.
She gave him vodka. In any case, the juice Juliet drank was a sedative, Jack clearly wasn't sedated...
He could have been. He said he blacked out and the next thing he knew he was waking up in the jungle.
He fell out of a plane.
Cindy assimilated 'quickly' because she realized the Others had altruistic motives and meant no harm (unnecessary harm that is). The Others nabbed her because she was on the List. Also, no one new the plane was going to crash beforehand except Abaddon and possibly Jacob (he either recruited the O6 intending them to arrive via 815 or Flight 316).
It is possible she was manipulated into boarding flight 815 by the Others.
The Others had NO idea the plane was coming. Hence their surprise.
Libby was supposed to use the boat to get to the Island. When she gave the boat to Desmond she slowly spiraled into depression and psychosis, much like Jack. At this time she started seeing things, much like others who have left the Island. As a result, she was commited to Santa Rosa.
Libby was in the mental institution, as a result of depression following her husband's death (and meeting Desmond), and took a liking to Hurley because she thought he was talking to her husband "Dave" in the afterlife.
It is not actually Libby in the mental institution, but a twin sister. This may explain why her hair color is different. This may also be the reason why Libby becomes a psychologist in the first place if her sister has mental issues. This theory also plays into the many themes of duality on the show.
The nurse who gives her the pills calls her by name. It's definitely Libby, not a twin.
The shot of Libby in the institution is a flashforward not a flashback. Hurley ends up back in Santa Rosa after leaving the island as one of the Oceanic Six. We already know that he sees dead people at that point in his life (Charlie etc.), so why not Libby. This is before the point in the show where the flashforwards start but that doesn't mean they couldn't have slipped one in for fun.
If she was a ghost then it doesn't make sense that the nurse gave her pills.
The woman in the mental hospital is actually Libby from the alternative timeline, who has somehow crossed over. Libby who met Hurley on the island wasn't lying about not recognising him, because it wasn't actually her in the mental hospital.
Libby is not a clinical psychologist. No Clinical Psychologist would call what was happening to Hurley (on the cliff after Dave jumps) a "panic attack." A panic attack does not mean standing around looking nervous; panic attack symptoms include hyperventilating, chest pain, sweating, and overall serious anxiety.
True, the symptoms of a real panic attack are distressing to say the least; but perhaps some artistic license should be granted. If they were to portray Hurley in the midst of an accurately depicted panic attack, any reasonable exchange of dialog couldn't occur. All in all, the symptoms were intentionally played down for dramatic effect.
Any real clinical psychologist could not have described a hallucination as a panic attack. The two things are very very far removed.
Possibly evidence she lied about her profession - possibly a production error.
Possibly a euphemism rather than calling it what it is.
Libby may have needed to choose a profession at random, so, with her experience in a mental hospital, chose a clinical psychologist because that's a job she knew pretty well.
Libby was working for the Vik Institute, where they experimented with autistic savants.
Her Husband, David
A character we haven't met.
She was genuinely in love with him, and genuinely emotionally distraught at his death, leading her to give her boat away "for love" and causing a spell in Santa Rosa Mental Institute.
There's no David. David it's like Hurley's Dave, or IT'S Hurley's Dave. Her medicines were Hurley's medicines too.
David is Dave, meaning Hurley's Dave. For one, They have the same first name. Also, Hurley sees GHOSTS! Dave was at the hospital while Libby was there, and Dave keeps urging Hurley to do bad things for his well being because Dave notices that Libby keeps watching Hurley. Another thing is while on the Island, just around the time Hurley starts dating Libby, Dave shows up and bluntly put tells Hurley to kill himself.
David was one of the two people who died in the collapsing deck accident that resulted in Hurley being committed to the hospital. The timeline fits perfectly for both Hurley and Libby, plus it's consistent with the theme of characters' lives intersecting when a loved one dies. (Shannon's father dying in Jack's hospital, Sawyer buying Christian alcohol that likely contributed to his death, etc.)
Libby is a "bad" person. The Others kidnapped all the "good" people from the Tailies camp, but did not kidnap Ana Lucia, Eko, Libby or Bernard. It is obvious why Ana Lucia and Eko were bad people, but Libby and Bernard are still unclear.
Not necessarily true. Both raids on the tailies resulted in casualties for The Others (Eko kills 2 the first night, Ana Lucia kills one the 12th) Then on the trek back to the beach Cindy is taken even though she wasn't on the list of 9. It's possible they just didn't get around to Bernard or Libby yet.
Cindy wasn't on Goodwin's list, but it's been made clear that Goodwin's list and the Lighthouse candidates were listed for different reasons. She did ultimately end up at the Temple.
The Others tried to take Eko on the first night. Before Goodwin told Ana Lucia that Nathan wasn't on the list "because he wasn't a good person", he listed traits like 'strong, athletic.. threats' to describe why some tailies were taken and others weren't. Ana Lucia located 1 list of 9 tailies on the female Other she killed - perhaps the other Others had different lists: Cindy could have been on another list. Personally I think the Others came back for Cindy because she had already forged a friendship with Emma and Zack, and she could help calm them - perhaps the kids even asked for her to be able to join them....
To expand, when she was murdered, Michael shot her out of panic, he had no intention to kill her in his mission to free Ben. This would explain why she appeared to Michael several time in Meet Kevin Johnson; and why Michael became a whisper and could not move on, because he cause the death of someone who was not ment to die.
Maybe Libby did a bad thing (a crime) and took an Insanity Plea?