Since checkpoints are more about revenue than drunk driving, I dont see a problem with this. The cops are more interested in nailing the .08 drinkers that probably arent too bad off than the .25 drunks. There are more of them, and many dont even realize that they have had enough to drink to blow .08.
Another kind of checkpoint. . . “Are you a U.S. citizen?”
http://www.youtube.com/watch?feature=player_embedded&v=fDCXzqgD99o