This is not an umpire problem - you can inspect bats all day long, but that doesn't mean, a different bat can't be pulled out of a bat bag.
This is a SCHOOL, COACH, and PLAYER issue only. Not to mention, the ejection is not for one game, but TWO! So, you are only hurting yourself and team if you use one of these bats. And, as far, as a player using it and saying they didn't know - JUST ASK SOMEONE - if they don't know - then use one that you know is LEGAL until you get a correct ruling on the bat in question.
Have you seen the list of non-approved bats - no one can remember all of these. In my opinion, if they want to make changes to make the game safer, then just make the change to wood - PERIOD. No confusion!