There is nothing wrong with DIY, but in this case, its a high school in question. There is absolutely no reason that unlicensed people should be doing any of the work there.
As an aside, when I was in my first year of apprenticeship, one of the old plumbers came to give a demonstration on lead. He brought some lead sheeting and a white gasoline blowtorch and his lead working tools.
He proceeded to show us how to make 4" pipe from sheet lead, how to make 3/4 inch water pipe and how to cut a wye into it and wipe the joint to seal it in.
None of us were able to do any of the work properly, but he made it look so simple. The next week he brought an old buddy of his, another old plumber, and the two of them did a burned lead joint.
We have all but lost those skills in most places south of the Mason Dixon line and west of the Mississippi.
The last burned joint we had to do we imported two union plumbers from Boston for three days to make repairs to an acid line in an old battery remanufacturer in North Little Rock. Those guys were both in their 50's. We paid through the nose and treated those two like royalty while they were here.
The Olympics are wonderful, and I truly respect the folks that train and dedicate their lives to mastering their sport, but my true heros are the guys that dedicate their lives to teaching the young the real skills of our profession. We could have cut all that acid line out and replaced it with glass to the tune of a few 100k, but we convinced the owners that it was cheaper for them to just let us fly in some talent to repair and replace the worn sections to the tune of about 30K total.
The supply house needed a heavy duty truck to deliver the lead for that job. They contracted with an armored truck service. No one else had a small enough vehicle with stout enough suspension to move that much lead into the tight spots we needed it delivered to. We didn't want to handle it too much and waste time bending and deforming the rolls.
I know I'll never be part of another job like that, and I'm glad to not work in such a toxic and awful place, but those two guys from Boston probably saved several jobs for the workers there at that small factory due to nothing but cost savings. And all because someone took the time to teach them one of the most rare of plumbing skills.