I did get a vehicle impounded despite reciprocity here in cleveland, because I didn't have proper OH registration. The law said I didn't need it, courts sided with me and dismissed it, because well, that's the law, but the officers at the time had decided that they knew the law, and that my bike should be impounded anyway. Long story short, despite the case dismissed and reciprocity being legal, the police still managed to extort almost 400 bucks from me by holding my bike hostage at the impound yard, regardless of it's legality.
moral: just beware, cops can be total shit. questionable legality, even when legal, is enough for them to give you a big ol paprika covered pineapple up your asshole.