You can usually attribute the call(s) to poor vision, wishful thinking or pressure exerted from an insane parent. My kid has learned to accept the fact that on average there will be 1 or 2 contestable calls per match. Whatever the case may be, it's best to teach your kids how to deal with Captain Hook and just move on.
There won't be more officials. There won't be a ZERO tolerance policy. There won't be a contract that parents/kids sign before each tournament. There won't be a public facing website with names and pictures of frequent offenders.
If you teach your kid to hook back, you've failed as a parent. It's better for junior to focus on reducing unforced errors and building up the mental toughness arsenal to deal with those blurry-eyed moments that may occur during a match.
A hook loses, even when he/she wins. A champion is a winner, even when he/she loses. If you can teach your kid that, you're a 1st team All-American parent.