I really see the entire situation as different than the NET/Bass Pro situation. With NET, Ted was, from what the consensus here seemed to be, making an effort to nail the big, new, shiny competition, which had the potential to hurt his own business due to the lack of 3rd gen Glock sales at any other shops. (I won't judge on the mail order ammo thing because the story was never corroborated). He ratted them out because their corporate legal department made a mistake and he stood to gain from it.
But here, Jim Sheppard had nothing to gain. Easton isn't that close to East Bridgewater, clearly not close enough for the explosion of a house to harm him. But, if this guy was a repeat customer who consistently came in acting weird (I believe madmarc0 said he once literally dragged his six year old in the door, whiel drunk), and then boasts about "drunk and boom", then I think Jim made the right choice in following his conscience. It's sort of like that NYC case where the woman was getting raped and all the people were just standing at their windows watching, doing nothing. I'm sure at least some of them feel like shit now. (I know its not a perfect analogy since this is a victimless crime) Jim made his judgement based on the evidence he had and based on whatever principles guides him, and I cannot fault him.
On the other hand, even though I wasn't sure at the time, since the Bass Pro fiasco, I've been by North Attleboro several times, but only to stop at AFS for ammo. I haven't entered NET since that day and don't think I will be doing so again.
Take it for what you will. I don't like setting rules for what I believe and what I don't, I like to take it on a case-to-case basis. In this case, I think I will patronize ZHA in the future should I ever be in the Easton area.