Jon would have left at the first sight of random hugs from strangers if he hadn't promised a couple of people (primarily his sister and his girlfriend) that he would come. It's not that he doesn't like celebrating things, or hugs. It's just that he doesn't trust strangers touching him, even when they've got a smile on their face. Having a wolf at his side doesn't help as much as he would expect it to; Ghost doesn't so much warn people off as attract extra attention from those who want to meet him.

So he's not surprised when he's trying to find an out-of-the-way place to get away from the random hugs and finds that someone's already there. It means he's not the only one who wants to avoid the hugs. He smiles a bit sheepishly. "We're not the only ones who had that idea. We'll find a different corner."