Can i turn the bluetooth off automaticity when I lock my iPad

This year, my school got ipsds for all the freshman. they also recieved a case with a built in bluetooth keyboard. technically the keyboard velcrows on to the case but they keyboards were made to work with the case. anyways, the issue we have been having is that the freshman forget to turn the keyboards off before they close the ipad and the keys get pressed. this causes the ipad to try and unlock and then they get locked out and their ipads disable themselves. then us members of our tech group need to restore them and its becoming a pain. my question is: is there a way to set up the ipads so that the bluetooth automaticly disables when the ipad locks, so that the keyboard wont do anything until they unlock their ipad again. Thanks!