No, it would not be a good idea. Some people get loud after one beer, some get loud after 5, others (like myself) can drink 10+ and still be calm and quiet... heck, some people are louder than a drunk without touching a drop of alcohol.

If someone becomes too intoxicated, then follow policy and cut them off. Arbitrary limits serve no useful purpose, except to give a feeling of moral superiority to those who feel alcohol is "evil".