For me it's fair enough that someone who isn't drinking doesn't end up paying for everyone else getting sozzled before, during and after a meal. I eat with the same crowd most Saturday lunchtimes. Some don't (always) drink and some drink plenty. We generally have the non drinkers pay less then split what's left evenly.
It should also be remembered that some folk are tight for cash and they shouldn't be excluded because they have to watch what they spend. I'm happy enough to help these people out (we've all been there) instead of embarrassing them.