Why *shouldn't* you be arrested if those two beers impacted your ability to drive? Why should other members of the public be on the line for your "those two beers didn't impair my driving
that much" opinion of your abilities?
There are two levels of driving alcohol offenses, by the way. I can't speak to what they're called everywhere, but here, there is: 1) "Driving While Ability Impaired" (under a .08, but your ability to drive is impaired to the "slightest degree"
; and 2) "Driving While Intoxicated" or "Driving Under the Influence" (where either: a) your driving is really bad or; b) you've got above a .08).
So, if you blow less than a .08, you're not
necessarily going to be convicted of anything. But if you're at a .01, you can still be convicted of the lesser offense if your driving was at all impacted. So, if you look sleepy, if you swerve over the line, etc., you're busted if you've got booze in your system.
Might seem like a draconian, zero tolerance, approach. It is, and it's meant to be - a whole lot of people are dead because of alcohol and cars.
This is coming from someone who's driven while absolutely trashed, by the way. It's a major problem; some pretty reliable studies show that you'll get caught once for roughly every 200 times you drive drunk.