I gunned a game in Oklahoma at a tournament when my son had graduated from high school and was going to go to college. Both teams had all kids either drafted or going to college to play.
The starting pitchers were both about 85 MPH at the top end, one right-handed the other wrong-handed. The lefty's dad asked me what I had on his kid. I told him & he was surprised, said he is usually 90. [Every kid in Texas throws 90 mph.]
I have gunned a long time and many pitchers. Unless there is injury, I don't get wide velocity reads. I can get an 82 - 90 when the pitcher cuts it, two seams it, etc. but the top doesn't usually read different unless there is a physical problem with the kid. Some high reads are when the bat touches the ball -- I just don't count those.
I do believe the intent to throw hard is important to throwing hard. I think it should be taught as the intent to throw "fast" and not "hard." Hard is often tense and the ball comes out slower.
The other problem with the intent to throw fast or hard is what you all have said -- (1) you may not throw well & (2) it may not be what is best for health reasons. I believe my kid had too much of an intent to throw hard and never really had a pitcher's mentality. The second one does, but he is only 12. The first one was really a hitter, position player who could throw hard so was made into a pitcher. Looking back, he should have hit and would have had a plus arm in the outfield.
I want to convey this so that some parents can temper their desire for the kids to throw hard -- it may not be the right approach. I agree with TPM on what she said above and believe her kid is on purpose or by accident being brought along very well. I also have a feeling that CaDad's kid will pitch for a long time from the comments he has made.
I look forward to watching these players in MLB. I can say I knew the parents from this website.