Some time back, I was chatting with the licensing officer in our town (he's since retired). He said that he once stopped a fellow from New York who had a NY state CCW and was carrying in MA. He told the guy "don't do that," put the now unloaded gun in the driver's trunk, and sent him on his way. He figured that if they guy had gone to the trouble of getting a NY State CCW, that he was most likely a decent guy, so what would be the point of arresting him?