Actually, the sub-topic of the requirement that police announce in advance the time and location of sobriety check points has not been discussed much on this thread. In California, that is a requirement. Furthermore, again in California, they are also required to leave an "out" for motorists in the event they come upon the check point and do not want to go through it, i.e., there must be a road where motorists can turn off if they so desire, after the check point becomes visible.
That in no way alters the fact that being able to look inside cars which are randomly stopped at sobriety check points, is a huge "plus" for law enforcement officers, who never pass up the chance to do exactly that with each and every car that goes through.
I might also add that announcing the date, time and location of the check point in advance has very little effect on the number of motorists who pass through the check point because most motorists never see the article in the newspaper making the announcement. Also, the turn-away option has little effect because motorists either fail to realize what is up ahead until it is too late (police often disguise the purpose of the check point, leading motorists to believe there is some kind of road work going on or it is merely a license checkpoint) or because motorists fear that they will be pursued if they elect to turn off.
I still can't figure out what you are arguing though. Is it the checkpoints themselves? Because I dont' see how those are a violation of the 4th. Checkpoints like that are generally set up when police know there is a high degree of probability that motorists will be driving drunk.
Or is it that such a checkpont allows them to look into your car? If that is the case you dont have much of an argument either because it is simply your opinion that police use them to get a look in your car. An opinon that doesn't make much logical sense. They want to look in your car, so they use sobriety checkpoints to do it? Your argument would have to be that they care less about people driving drunk than the off chance of find some weed or something else illegal.
What I think I'm picking up from George, and he will correct me if I picking up the wrong stuff here

, is that he is arguing that the laws are written in order to give the police license to have a means to violate the 4th Amendment.
And he has made a pretty good argument for that.
I think I'm leaning more to your point of view here, however, that it is a stretch to assume that the law was written for the purpose of having a means to violate the 4th Amendment.
On the theory that any law can be intentionally or unintentionally manipulated or misinterpreted by the ignorant or corrupt, that in itself is not sufficient to assume intentional or organized malfeasance or overstepping one's intended authority.
I prefer to think that the intent of cell phone laws, drunk driving laws, requirements for driver's licenses, insurance, registration, etc. are all appropriate to promote the common welfare, and check points are a reasonable means of enforcement.
I don't think we can automatically assume that the check points are intended for the purpose of anything else. I can see how they also could be used for the purpose of having an excuse to look into people's cars,
though around here if they're looking for somebody specific, they don't usually conceal the fact that this is why they set up the checkpoints.