That's one part that makes checkpoints "reasonable". They DON'T stop random people. If the stops were random or arbitrary, they WOULD be unconstitutional seizures. The court determined in Sitz that the stops were reasonable in the effort to protect the public from drunk drivers as long as they stopped every car, or every tenth car, etc. I think the reason why license checkpoints are still being considered "constitutional" is because they haven't been challenged yet. In Brown V Texas, the initial reason for the stop (license checkpoint) was never challenged at the lower levels so the Supreme Court didn't address it. Mr. Brown had a ****** lawyer. I'm not even a lawyer and that's the first thing I would have challenged.