Thank you for making me do more research
You, of course, are correct, unless you are under the influence you are good to go, regardless of the type of establishment.
I was in Mass when pondering this and now that I've done more research, the laws there are the same as Maine for carry in a restaurant or bar. I'm not sure where I incorrectly learned that one couldn't carry in these establishments but I was wrong.
Getting a MA LTC was a huge pain in the ass, and you literally have to renew six months before your LTC expires because their bureaucracy is so shitty but I'd advise everyone to go through the process and get a MA LTC. I feel so much better when in Lowell, Holyoke, Lawrence, Boston, etc.