You are reiterating my complaint about Martinez-Fuerte while stating that I didn't read it. Even stops that don't lead to searches are seizures that implicate the fourth amendment rights. Martinez-Fuerte acknowledges this, but then says "oh it's not that bad, and if the government has what it says is a compelling reason, go ahead."

Bad lane change is explicitly probable cause -- it's direct witnessing of a traffic code violation. It's usually pretextual: they have some other reason they don't want to articulate that might not pass constitutional muster, but pretextual stops and even searches are unfortunately allowed. And no, they're not supposed to pull you over to check your insurance absent some reason to think that there's a problem with it.

Stops without probable cause are bad not just because they are interruptions and wastes of time, but because they allow more opportunities for other abuses such as pretextual searches.

Administrative checks for commercial trucking (i.e. weigh stations) would be a better instance for stops that no one generally complains about.