The bottom line on bat rolling is it alters the BPF or BESR rating beyond the legal limit. As a parent how would you feel if the illegal bat your son used badly injured or killed a pitcher or conrner infielder. My son play third. If he got crushed by a line drive I'd have the bat confiscated and check. If illegal I'd sue the opposing team, coach and parents and bat rolling company for everything that could be taken from them.
However, the bat rolling companies waive their liability by insisting their service is for hitting exhibitions only. What the customer does with the bat is their own business. I'd rather a parent soup their kid up on steroids. Then they're only threatening the health of their own kid.