Not a lawyer, but I'm with you on this. The rebel side of me wants to tell the officer to pound sand, but the upstanding citizen side of me just wants to comply with the request so that I/we can get back to our journey.
I betting the officer is hoping the upstanding citizen comply's so he don't have to do more paper work for hauling you in!
I betting the officer is hoping the upstanding citizen comply's so he don't have to do more paper work for hauling you in!