Oh good. They do that if they know you're waiting for someone. Or try to. Doesn't always work.
No one's mentioned a thing about anyone disappearing from their points for as long as any of us have been gone so the theories are: a) we're copies or they're copies, b) if we can switch dimensions, we can switch right back to where we were. The few people who have disappeared and come back, they don't remember being here.