John, I am no longer a high school teacher. The last school I taught in was a private school for emotionally disabled students who the public high schools couldn’t handle. It closed, and that was the end of my teaching career because no one wants to pay you for 20 plus years of teaching experience. Also, once the principal or director sees that you are older than they are and may know more than they do, that is also a disincentive to hire you.
I served in the military prior to my teaching career, and yes there are teenagers in the military serving right along with experienced service members. I was one of them. The military is a culture unto itself with a very long institutional memory, and ways of doing things that have been in place for a couple of hundred years. Due to the Uniform Code of Military Justice, there are few behavioral issues because if you don’t follow the orders you are issued including being late or absent without leave, there will be some serious consequences including losing rank, losing money, being restricted to the barracks or ship, extra duties, and bad paper in your permanent file which will affect future promotions and postings. You also wouldn’t be eligible for a good conduct medal. All of those punishments can be issued by the company commander without due process. You can request the due process of a courts martial, but then the punishments imposed can include the stockade or even federal prison, as well as a dishonorable discharge which is something that will dog you the rest of your life.
The main thing that conditions service members to go along with the program is basic training. Everyone isn’t up for that because of the physical requirements, and the mind f — king that goes on every second during the process. The recruits get yelled at A LOT, and have to do unpleasant things that seem to make no sense whatsoever during the training, and they can’t question it. The drill instructor is not concerned with their feelings because he or she is trying to turn them into soldiers, and of course they have volunteered to be subjected to this treatment. I joined in the mid-1970s while there were still some draftees left over waiting to finish their time, and they were absolutely NOT going along with the program. The command stuck them in a special barracks and left them alone to drink and smoke weed because they were more trouble than they were worth.
Supervising a group of teenagers to do what is essentially forced labor sounds like an absolute nightmare. NO construction work is safe, and unless they can rigidly follow procedures there will be accidents aplenty. On a commercial construction site, if a worker can’t follow procedure they are escorted to the street and told where to pick up their final check. And by the way, not everyone is suited to do physical labor well, or even competently. If you think that any dummy can come off the street and set about to dig a properly graded ditch, you better check your assumptions about the people who work with their hands. An average kid with a high school diploma is no more ready to build out the framing for a concrete pad, set the rebar, and pour and finish the concrete than they are to do surgery. It takes years to learn how to do that stuff properly, which is why contractors do it now.