The high school level? Is it correct to assume that most, perhaps all, states follow the collegiate rules except for a few exceptions-- 48 minute games, 12 minute quarters; kickoffs from the 40, kicking off out of bounds gives the option of the receiving team taking the ball at their own 40 or a rekick from the 45; in some cases it may be agreed that a nondistrict game (which would not count in the standings for playoff positioning) can end in a tie. And otherwise, do all states now follow the college overtime rules?
I've had some discussion with football officials before, and I've never gotten them to agree with me about calling for a fair catch on a punt and then letting the ball go over and throwing a block. I do not think that should be unsportsmanlike conduct, as the current rule states. One said, "Well, if you call a fair catch, you're saying 'you can't touch me,' so you shouldn't be able to touch them either." I argue: that's true only if you make the catch. If you're fielding a punt, the coverage team can't 'touch you' before contact with the ball whether you call a fair catch or not; but if you flub the catch they can, even if you do call a f.c. Incidentally, I don't think I've seen a punt returner deceive a coverage team without calling for a f.c. by pretending he has the catch when he's 'up' on it going to let it sail over, hopefully beyond the goal line-- but I assume that is not a penalty. It compares to that trick the Rams pulled in 2015. So, to sum it up, IMO that's a good tactic to protect field position when the punt comes down inside the 10 or so.