In the "Re-Do" line, we see Desmond on the plane, which is suprising but possible. But why was he the only person Jack recognized? Because of a meeting at a stadium which may have never happened in this universe? Or because the rules do not apply to him?
He seemed cautious if he did know what was going on, but if Widmore was on the island at the time of the explosion, it is possible he died, and possible that Penny may no longer apply the same way to Desmond.
Was Desmond aware of the change? What do you think?