This won't be the answer you want, but - its quite possible that the behaviour of the individual concerned was quite obnoxious to the sober staff of the restaurant, who shouldn't really have to tolerate any kind of abuse in their workplace. I dare say that the staff of the restaurant also had their night ruined, and wouldn't have reacted in the way they did unless they were quited sorely offended at something... It's easy to underestimate how poorly our friends come across to other people who don't know them, when they are drunk. We know their intentions, but others don't.