Well, if you stopped everyone on the street and demanded every time you get in the car you need to provide a breath sample, apart from moving a step closer to a Big Brother police state—it is a step closer to that, but leaving that aside—it would no longer be random; it would be universal. You might find other constitutional matters or problems with it, because we can't require all our citizens to provide bodily samples just for the sake of it, but yes, you would remove certainly the randomness of it.
On February 25th, 2009. See this statement in context.