Jimmy Cirrito, owner of Jimmy's Old Towne Tavern brought up a very good point about the Fairfax Gestapo cracking down on non-driving drinkers over the legal limit.

Since everyone is required by Virginia law to have a BAC of .08 or below, there is no need for designated drivers, because everyone would be legally able to drive. There you go. Problem solved.

Fox News' Judge Andrew Napolitano noted that while when you enlist driving privileges, you waive away your right not to submit to a DUI test, you have no such obligation if you aren't driving. You still have a Fifth Amendment protection against self incrimination, and can simply refuse to cooperate. Of course in reality, you'll probably still be arrested, but in a court of law, it should hold up.