What could go wrong? Even if everyone on this forum that understands guns wanted to be a part of this there's almost no way to know what a legal or illegal gun is just by seeing someone hold it. How many calls are they going to get about a registered "assault weapon" they see someone with? Or " OMG "he's got a pistol it has to be illegal" from some dumb schmuck.
This is why anytime I load a gun into my vehicle I back it in as far back in my driveway as possible and load them into the bed. Almost assured no one can see it.