It's an interesting position, but may still leave you with the same problem. A fair proportion of the disruptive students actually want to be at school (since that's where everyone else is) -- so even if you make it voluntary you will still get students being disruptive. In the end you still come to the conclusion that you have to enforce the rules to make education effective. (Also, anyone who's ever watched a normally well-behaved classroom in the hands of an inexperienced substitute can believe that discipline makes a difference!)