Hi Joe, First I'd like to commend you on getting kids started into RC "Anything." Just to keep the kids off the streets and they will be learning something that they can take with them through out life. I too wanted to start an indoor flying club (not so much a competition) at my VFW Post. One of the factors that met the demise of this club was that many of the Guys worried about kids getting hurt. I suggested the parents sign waivers to protect our organization from any law suits. Unfortunately the idea of a waiver did not fly (no pun intended) because many felt that would not be enough to protect us in this "sue happy society." Long story short....my idea got shot down because of budget and law suit issues.
What am I trying to say? Try and get a waiver in place to protect all involved
Again, I commend you Sir and wish you and those involved the best of luck. Have fun.