To play in real time please consider the live chess settings.
As to vacation time it should always be allowed. Some tournaments go for a very long period of time and it would be impossible to not expect some players to need some time away from a series of games for a week at a time.
I realize that many people like to beat the "no vacation" drum from time to time, however I suspect that most players do not have issues with this.
As a member of the "Fast Players Group" and someone who tends to like to play Chess in "real time", I think a excellent way to prevent or at least diminish cheating (as per Eric'a article) is to limit things like time outs and vacation time during tournament settings. Under a tournament setting it would seem a little suspicious for a person to take a bunch of vacation time only to come back and play the right move. If a tournament has a 1-3 day limit then players should follow this guideline or not participate. I accidently joined a move/15 day game and it is driving me insane. Let's hear it for quick and realistic play.
Cheers
Sunkenchess