Comment by mothballed

They'd have not forced license plates to be displayed at all times to begin with, as they are a search of your papers without probable cause your vehicle is unregistered. Private ships in those days (probably the closest equivalent of something big and dangerous that could do tons of damage quickly on the public right of way) did not have required hull numbers or anything like that. Of course that doesn't totally solve the flock problem, but makes it a lot harder.