From Doc Jensens recap
This moment was staged to deliberately echo the scene from the season 3 episode ''One Of Us,'' when Jack, Kate, and Sayid returned from New Otherton, bringing Juliet with them. When the beach crew saw her, the happy-huggy moment abruptly ended, and everyone gave her the stink-eye (especially, ironically, Sawyer) — just like Jack and Ben traded suspicious looks in last night's episode. We learned at the very end of ''One Of Us'' that newbie Juliet was indeed shady; she had been sent by Ben to spy on the camp. (The moment was mirrored, I think, by having ''Dr. Linus'' end with Widmore's submarine spying on the castaways.)