Sayid built a 'luxury' tent as a surprise for Shannon. It was very private, with four solid walls made of airplane wreckage and tarps. The roof was high enough to stand up inside, and it was romantically decorated with makeshift candles, flowers and fruit. Shannon had a vision of Walt standing in the doorway on her first night in the tent, and died the following day. ("Abandoned") It doesn't seem that anyone used the tent again.