I kind of understand what blackSSRS was trying to say. When some people get hammered, they think they can do anything.
If a person who is hammered is only just then trying to decide if they're okay to drive, then it's too late. People need to be proactive about it and recognize that, if they're going to drink heavily, they shouldn't even drive themselves to the bar in the first place. Get a cab or have the DD drive everyone.