Right, I agree with this too. A more specific question would be more helpful since we could advise you about it in general.
For example let's say a child is doing their beam routine and does side handstand dismount with no quarter turn (level 2 dismount) in levels 3-5. This is a large deduction. And very common mistake. Sometimes it is just a mistake and they can do the dismount so they do it again correctly and only get a fall plus execution on both attempts (still often hefty). But in level 3 it is common that they might not actually be able to do the dismount yet, or they cannot do it consistently in a safe way, maybe they twist too close to the beam, or pike down and crash towards the ground, etc. all common.
So if someone here asked, I would tell them what deduction might occur from the scenario, but also would advise them that it's a very common error and their child shouldn't attempt the full dismount until they're ready, so the parent should not mention anything. If the child goes up into a handstand that is not fully locked at vertical, and then tries to "force" twisting they will land on or hit the beam. Sometimes a coach may knowingly need to instruct your child to do something that is a deduction, but the child will need to perform it that way for safety or progression reasons. This is just one example. They want the child to focus on another error, or to focus on completing the routine safely. If the parent jumps in and tells their child that they could have scored higher by doing xyz instead, then the coaching is undone. I'm sure you can see how this is a problem. Also, I have had parents tell their child things that are untrue, such as their child is getting a deduction because I stand between the bar on their tap swings (even if we did, I still would because I want to minimize the risk of their child breaking their neck. But it is not a deduction) or that if you go on a lower (allowable adjustment) setting you get a lower start value (also not true). This will cause their child to not trust the coach.