Where did all the beer go?

I recently read a post at homebrewtalk where a poster says that he's convinced that kegs have some kind of a crazy beer evaporator inside. I did not realize this until today. By the time you are done racking you probably have four gallons of beer in a keg. According to Google four US gallons = 32 US pints. Here is where the math comes in, 32 US pints + one week + magic beer evaporator = no beer. Yes it's all gone. Granted I lost a little foam trying to get the carbonation just right the first time around, but I never thought it would be gone in a week. Oh well I guess I will just have to brew another batch.