[Colo Blue]

USSSA in Colorado requires you to check the bats prior to every game. Make sure the bats have the USSSA thumbprint on the bat. If a batter is caught using an illegal bat, the batter is called out and runners are returned. If it is the first offense a team warning is given. If it is the second offense, the batter is also restricted to the bench, and the coach is ejected.
USSSA does have a few other differences. They allow you to have two (2) AP's (additional players) in the lineup. So you can bat 11, and have twelve players listed if you use the DP/Flex.
Also they have a screwy short handed rule. You can play short handed, taking an out for the absent player(s), and can continue playing with 8 players. So if you are batting 11, you could have three absent players and still continue the game. Plus it doesn't matter why the player is absent, including an ejection.
Courtesy runners are a little different to. A courtesy runner can be used for the pitcher in one inning, and the catcher in another inning. Just not in the same half inning.
There are other subtle differences, if you read the rule book.
In Colorado we use the college CCA Manual for mechanics. I'm not sure if that is national or not.