When I worked in Torrington, CT, a plainclothes officer or officer off duty came through the carwash to get his patrol vehicle washed and vacuumed. He might have been State Trooper, he might have been local PD. Standard car wash procedure for me being the greeter and salesperson was to handle the driver side. First thing I do is notate the position of the seat. I finding something that lines up with another mark in the vehicle is the best way. I then slide the seat all the way back, and start cleaning. Guess what my vacuum nozzle bumped into under the seat? A loaded, racked and ready to roll full size polymer pistol (glock 22 or similar). I removed it, ejected the mag, ejected the round in the chamber, reloaded it into the mag, and then put the gun in the glovebox. I walked inside and gave him a private ration of shit in the office. The jerk then had the audacity to ask me in an accusatory way 'What were you doing under my seat?" "Cleaning your car like you paid for, you idiot" I may have used less kind terms than quoted, but I am paraphrasing to keep the language here clean. The final word was something along the lines of "if this ever happens again all I am going to do is take pictures of YOUR gun in my hands with serial number and email it to whoever I think will make the biggest stink about it."
Which was the stupidest possible move to make in that scenario, but I was pissed off. I was 22 and an idiot. Possibly more so than the officer. The last thing you do is threaten someone who has the ability and authority to make your life a living hell if they wanted to. I never saw him again, and nothing more came of it, thankfully.
Likelihood of the gun going off while cleaning? Not likely. Likelihood of something interacting with the trigger and while me or one of my guys is doing their daily grind? A distinct possibility as I've found things ranging from coat hangers (guys bring their uniform to work hanging up) to condoms (thankfully not used), pens, bits of string, etc in police cruisers in 5 years of working in carwashes. Lots of foreign objects that could easily get wrapped up around the trigger and caught in the suction of the vacuum while we are quickly trying to clean.
Guns don't shoot themselves, but someone unaware of their presence doing normal, daily routine things will certainly have a risk of having it go off.
Should this guy be punished? In my non-judiciary opinon, hell yeah. What should it amount to? Suspension of LTC for sure. Fines. And community service. Preferably volunteering somewhere or with an organization that teaches the responsible handling of firearms, to drive home the point.
But its MA, and he's losing his LTC and possible going to have endangering a minor added on. Speculation only on my part though.