That may be the rule for particularized searches (I don't know one way or the other), but "papers please" road checkpoints are common[1]. U.S. citizens are theo

That may be the rule for particularized searches (I don't know one way or the other), but "papers please" road checkpoints are common[1]. U.S. citizens are theoretically not required to show papers. In practice, theory and practice diverge. https://en.wikipedia.org/wiki/United_States_Border_Patrol_interior_checkpoints https://en.wikipedia.org/wiki/United_States_Border_Patrol_in...