On the flip side of the OP's story....
Setting the Scene... Me, with my 5.11 Freedom Fries TShirt driving around in my car with NH Plates (Firearm Related Vanity Plate)
Last Tuesday, I was going up Route 2 out past Gardner at a rather expeditious rate of travel, slightly distracted (but still looking at the road) due to work crap, and missed the Trooper sitting on the side of the road. I see him pull into traffic, put his lights on, so I moved to the right lane and got into the flow of traffic. He gets in line behind me (No lights on) and follows me off the highway as this was my planned exit.
Once I turn onto the surface street from the exit ramp, he puts his lights on and we both pull over to the side of the road. After we're stopped, he does the whole touch the trunk thing as he walks up to the window and I hand him my license. He asks for the registration, tell him I'm reaching into the glove box to do it. As I'm doing that, he asks me if I have any firearms in the car. I answer truthfully (yes). He asks where and I say my right hip. As he's opening the door, I assume to remove from the car, I add that I have a license for it (Should have lead with that). He pauses for a moment and says "You have a license?" "Yessir" He asks for that and checks it out. "I didn't know they issued these to out of staters, hell, We [MSP] even issued it". He starts walking back to his cruiser and remembers to ask for my registration, which I give him.
He goes back, does his thing and walks towards me with the "dreaded envelope". I say dreaded envelope because the only time I remember seeing one is when I've gotten a citation. He says he's only giving me a written warning and to slow down (a lot). So now that he's handing back my cards and registration, I asked him what made him ask about the firearm, was it the plate? He said "No, it was your TShirt". He gets back in his cruiser and I pull away.
Granted, this is outside of the Metro Boston Evil Influence Sphere, but overall not a horrible story of dealing with a Trooper.
I can't decide if the novelty of my Non-Res LTC swayed his decision to write me at least a 200$ ticket or what, but I'm glad he didn't impose an extra tax on me that day.