In my ideal gym, if an athlete quit at any time during a season, they would be responsible for the fee for that month, the next month, and competition fees that they would have had if they had stayed on the team, and a dropout fee of $100 that goes to boosters. The future competition fees would be for the athlete that replaces them and I wouldn't make that athlete pay for a second team's tuiton. Also, I would only do this all if an athlete quit unexpectedly, was asked to leave because of a behavior problem or missing a comp, ect, but not for injuries or any big changes (family member dies, moving, ect).
Also, when I was in high school, my high school team made us pay for our $200 uniforms during both years, even though I used the same one both years, but then we couldn't keep them. When I didn't come back junior year, the head coach charged my mom's credit card for new uniforms, athletic fee, ect, even though I had said at the end of my sophomore season that I wasn't coming back. I was unjustly charged about $850 dollars in total. My mom freaked when she found out about my coach stealing money, and got a lawyer. She didn't end up suing because my coach payed us back all the money for my freshman and sophomore uniform, and the stuff from my nonexistent junior year. Also, she had to pay back all the cheerleaders that ended up paying for uniforms any year, when we learned later that she had taken all the money because boosters paid for uniforms. It was unbelievable, and she was quickly fired.