There are 'no vacation tournaments' already. And when someone's online, it doesn't mean they are studying your position. Maybe they just want the joy and pleasure of coming home to Chess.com, and curling up to the warm fireplace of the forums.

When you are signed in, you are online. Like me, they may just keep themselves signed in on their computer and may be doing something completely different.

I agree Karl. Vacation time appears to be way too long in many cases. The momentum of tournaments is lost when people are on endless 'vacations'.  Its just a stalling tactic in many cases. Takes the good out of tournaments.

I agree completely but there is nothing to do about it. Best advice: join No Vacation tournements