1baseballdad - Absolutely true that the rules were changed for safety. Also no doubt old bats perform better.
I do know a number of umpires and they hate this. The standard comment before the game is to ask coaches if the players are properly and legally equipped. Coach says yes and play ball.
They fear that before every at bat they will be required to inspect bats. Guess why? Lawsuits. The next pitcher who takes a liner off the forehead from an illegal bat will have a couple of parents and a lawyer looking for someone to hold accountable. Umps, coaches and school districts will all come into the line of fire.