This is one of the things I hate the most and it needs to get changed in school cheer but there is no entity out there who will do anything.
I always give people the advice to let the coach do their job but as the parent you have all the power of ensuring CP is in a safe environment. Here are a few options:
1. Have a meeting with coach and make sure it's clear you know the safety rule for using mats when stunting and tumbling. I recommend showing him/her from the AACCA or NFHS guidebook. Let them know you won't stand for an unsafe environment and if anyone gets hurt you'll be the first person who will let the principal, school board, insurance know that they are being negligent and liable. It's serious enough I recommend letting coach know you will pull your kid if you have to. BTW I've done this. Thankfully CP realized how unsafe it was and decided she didn't want to cheer senior year.
2. Go to principal if coach won't listen to inform them of the unsafe situation and liability issue and you will let the school board know if it doesn't change. You guessed it, school board is next step.
3. You can contact AACCA and inform them of the issue. Unfortunately I have not seen anything come from this in the way of enforcement, but I hope that is changing.
Sorry this is kind of long in a newbie thread but it's one of the most serious issues I believe is out there for school cheer right now. The price for negligence with stunting and tumbling on unapproved surfaces it too high and your child pays it. Parents need to know that AACCA offers a catastrophic insurance, but I have never heard of it being paid out. That waiver everyone signs saying they are acknowledging this as a "dangerous activity" always wins out.
*off of soapbox* Please resume stressing about your seasons.