It probably is not the threat of a parent suing that is the problem, it is more than likely an insurance carrier for something like an errors and omissions policy that insists on the school/district having the rule.Bro, many public schools won't even allow kids to bring peanut butter sandwiches from home. Instead of warning "Aiden, if you eat PB, you'll DIE!", Aiden's two moms threaten to sue the school.