Can you show me where the probable cause is in a random stop and search for a document!
If they can justify that I'm quite confident someone will come with justification for anything else light years from probable cause.
Certainly not. But, I suspect the courts are justifying it with some rendition of the ol' "when you're on public property -- especially when you operate a two-ton implement of destruction on public property -- you implicitly agree to ... (blah, blah, blah) ... for the public good."
Again, the difference is public vs. private property. I'm not saying I agree with it. I'm just saying that's likely the justification, the product of a very loose interpretation of the Constitutional language (as we're used to seeing at every turn).
Thus, coming into our private residences would still be a huge step from what we have here, stopping vehicles on the public roadway.