I agree that it is inappropriate to attend a meeting under the influence. You wouldn't, or should I say shouldn't, handle your personal affairs drunk so why would you handle post affairs in that manner?
I think it is a matter of common sense and I don't think you'd be out of line by suggesting members refrain from drinking until the meeting is finished. If somebody has a problem with that maybe they should not attend and/or seek some sort of help.
Hopefully somebody can help you find something in writing that supports this. Unfortunately, I'm not very familiar with Axillary By-Laws.