I'm far from well versed in sobriety checkpoint law/statutes, but I believe that they have circumvented many of the challenges to the constitutionality of the sobriety checkpoints by giving "advanced warnings" of the dates of the checkpoints and their anticipated locations in the local media (e.g., in the Dispatch, through local T.V. news broadcasts) a day or so in advance. So, while I agree with your assertion that sobriety checkpoints have been successfully argued as unconstitutional as well as your assertion that they must be carried out in accordance with specific guidelines, I believe law enforcement can, by way of their "advanced warnings," use sobriety checkpoints as a way of circumventing illegal search and seizure. Of course, there's nothing preventing any of us from claiming that police violating our constitutional right against illegal search and seizure, I'm just saying that, from what I understand, law enforcement has used the "advanced warnings" tactic as a preemptive defense against such accusations.