I can't believe I'm saying this, but I agree with RodDog - maybe for the first time...ever!
DUI lawyers will tell you, "Never blow." Not because you can get away with it that way, but because breathalyzers are notoriously inaccurate, and it can easily and incorrectly certify you're drunk, even if you're not over the limit.
Of course, refusing to blow creates a whole new set of problems, but a good DUI lawyer would advise you to postpone any testing as long as possible. It gives him more ammunition to refute their claims in court.
The only reason I'm offering this is I used to deliver live endorsement radio ads for a DUI lawyer, and this is what he told me. I've never been pulled over for DUI - not that I didn't deserve it.
In fact, I seriously doubt anybody who drinks hasn't gotten away with it at least once - probably many times! There but for the grace of God...
One good story: A recovering alcoholic who had been in AA for many years was pulled over, and the cop asked him, "Have you been drinking, tonight?" The man replied, "Tonight? No sir." The officer - convinced he was trying to dance around the issue said, "Okay, how long has it been since you had your last drink?" The man looked at his watch and responded, "Uh - 12 years, 7 months, 22 days, 13 hours, 44 minutes and 18, 19, 20 seconds."
The cop laughed so hard he just handed his license back to him and walked away.
Go Frogs!