I don't understand what happened here. If you were known to be completely within your rights to carry there, why did the LEO come to your house and make any issue at all? Shouldn't someone have just told the PRMA subjects that they were back in the United States (Maine) where such behavior has always been legal?
One of our group here had a similar situation about a year ago: He was gassing up at a nearby station when some Canadian tourist freaked out and called 911. The LEO spoke with the Virginian, explaining why he had been called, then went over and explained to the Canadian that no law was being broken. The incredulous Canadian left in a stae of angry perplexity, and the LEO came over to the Virginian, shaking his head saying "Canadians!!"
By the way, I still have fond memories of summer vacations at Grand Lake Stream and Big Lake. Beautiful state and great people! ( Don't get me started about my days in PRMA!)