JDeere, it's nice to hear about the pleasant interactions with police or MP in situations like yours. Frequently, we only hear about the bad. Sounds like his PR ratings went up alot that day!!
I've not yet been stopped by MP for anything (not that I'm looking to be stopped but I've probably just cursed myself now!) but I've had a couple of brief conversations when I've seen them tied up at a public dock. I've always found them to be polite, courteous and a wealth of information.