Yes it is, but for good reason I suspect. Christmas parties are fun but colleges have insurance to think about - and, I suppose, clear rules regarding the consumption of alcohol on-site. It would be great to think that staff would drink with moderation but that is not easy to police and most colleges are managed to an extent that there is no such thing anymore as a "blind eye". You'll have just as much fun down the pub, I suspect.
Dilemmas should be e-mailed to Donald Short at email@example.com