If the said person/s are Printing, I would not say anything to them. They are supposed too be resposible when carrying. That includes picking out Their clothes. Especially in MA., which is a Concealed state. If you're Printing, then you are a "wacker" as the infamous MA. State Police would call You. Someone who thinks they are cool carrying a gun; likes to show it off; likes to let Other people know they are carrying, etc. I know this because I already inquired about it with a couple of MA. Troopers (who, by the way are Dinks...but that's another story). If you are carrying concealed, then that means NO PRINTING too. Otherwise, even though You are actually carrying concealed you May get a MA. officer pointing his/her weapon directly at you. You better have a quick excuse other than the tight shirt you're wearing was the only clean laundry you had that morning to wear.
Note: The above scenario was towards carrying concealed in MA..
Again, to answer the question, NO I would not let the idiot person know they chose improper clothing for the day. They do not deserve to be carrying a weapon period!