It does look like they have a snorkle attached to them! Seriously, I got them from SWF on Thursday and about half seem to stay at the top all of the time. No, I didn't number them when I put them in the tank so I can't tell if the same ones are at the top all of the time. I was just wondering if others were seeing the same behavior.
My snails are hanging around the top of the tank also but I've noticed they're looking out the window at your snails across the street. Maybe your snails are in heat.