Tournaments are a very good thing for a young players game and there is a lot to learn from them so its good to get used to them. Here are some things i would like to tell you.
1. Players are supposed to call the score out. It doesn't have to be loud or obnoxious just clear enough to hear. If there is a scoring discrepancy the kids call the referee over and they each say what points they remember
2. Kids make the calls and the referees only overrule if the player asks them if they saw it. If they aren't asked they wont do anything so you can't complain.
3. There is a score card and kids are required to flip it although they won't be in much trouble if they don't. It is a good idea especially at the early levels.