That story about the deputy whose kid reached into his pocket stinks to high heaven. At best, the lackwit was pocket carrying without having the pistol in a holster. Shameful. He also had no situational awareness. At least as shameful.
OP: If you are not comfortable carrying a pistol for serious purposes ready to use, you are not ready to carry a pistol for serious purposes. The fact that entities in Israel have trained to work with firearms that are carried without a chambered round does not make it anything other than clownshoes. Barring the most unusual design/manufacturing errors, firearms of reasonable quality simply do not "just go off". Something pressed the trigger. Period. There are TONS of people who carry pistols like yours without any problem; M&Ps in various calibers, Glocks, etc. If there is a problem, it is the shooter. I have been carrying one model or another of a Glock for most of the last 25 years, darned near all the time. The only issue I have ever had was on a range, trying a technique that allowed me to put my finger on the trigger where it did not belong. The error was MINE. The pistol was not the problem - I was. That was in the fall of 1989, and that technique was discarded right then.
A good friend is an armorer and instructor for the Washington State Patrol, which issues M&P 40s like yours. They have had a couple NDs, at least one of which had serious consequences. (Idiot probably should have been prosecuted, and certainly fired, but that's another issue.) A command officer who maybe knows just enough to be dangerous thought it was a gun problem and it took a lot of effort to keep him from mandating increased trigger pull weights. Know and follow the 4 firearm safety rules, and it is virtually impossible to have an ND, or to otherwise cause unintended harm.
You need to do some significant research, and preferably obtain real training. Reading between the lines leads me to be concerned that you are simply not educated enough about firearms to take care of your own best interests. What training have you gotten about use of force, tactics, threat recognition and the like?