First, thanks for the tip about the cheap brandy
I didn't know about not being allowed in chat while drunk. Sensible rule but not enforceable. All you can do realistically is try to police the actual behaviour of people. If someone is a chilled and friendly drunk, there should be no problem. If they are abusive, then their sobriety is irrelevant.
As far as posting goes, people should be taking the advice of strangers with a large pinch of salt in any case. I would think if a poster gets abusive, they will probably be sorted out by the general community even before the mods get to them.