If this type of thing can bring the attention to the idea, then yes. If it stops even one person from driving when they shouldn't. I think there would be some people who would blow, not be over but close and realize that their blood alcohol is higher than they realized and choose not to drive. At least I hope someone out there would have it happen.
I voted "yes" but have a caveat. Find a way to provide the tests free. Fund dependable maintenance programs for bars/restaurants. Use a "key check" system to ensure over-the-limit drivers have a designated driver or a free taxi ride home.
I don't think most of those who desperately need to take the test will pay $2.00 to learn the results. Unless it's on a bet after a hard night of drinking and some yahoo decides to place money on who has the highest count. Guess what the winner/loser gets? I'm guessing another drink. Those are the wrong-side-of-the-road, one-eye-closed to stop double vision, and lane changing drunks.
For casual drinkers, even two glasses of wine can put them over the legal limit -- depending on the individual, what they ate, the time span over which those drinks were consumed. They may pay before they decide to drive. At the very least, they'll think before they drink two the next time.
Bartenders and restaurants are held accountable for serving people who've had too much to drink, but few challenge their regular patrons--or, even friendly, happy, lonely, quiet, strangers. Why? Tips? Avoiding confrontation? Have you seen a drunk denied another drink? I have, and it's not a pretty sight. So, they send an irate drunk on the road in search of a more accommodating bartender. Give bartenders solid data and some real clout.
"Take the test. If you pass, I'll serve you. If you don't, we can (1) call a cab, or (2) call the police to report public intoxication. Your choice. "