When tournaments are set up the TD has an option to make them No Vacation. Even without vacation, tourneys can take years to complete, depending on the time control. Without vacation, people would time out in more games than they do now and some tourneys have massive timeouts.
I could be wrong, but if you not currently in a round, say you are moving on to the next round, I think you can join another tourney. And if you aren't going to move through, and are still in the tourney, you can withdraw. You'll lose access to some tourney points but unless you are high enough placed, you won't get points anyway and they really don't mean much.
What do members think of vacation on tournaments? I dont think tournaments should allow vacation. If there is a hundred people and lots want to go on vacation this basically stops the tournament. Ive been in one now for 4-5 months and nothing is happening. If you are a free member you get to do one tournament at a time. I have since upgraded but theoretically could a tournament go on for years. If so once someone is locked in they have no other choice to wait it out unless they upgrade to play another.