How do you know this for sure
It has always been written that one needs to use "Lem 'em play"
So your trainee won't be subbed for even if there's no back up
6+ seasons of testing tells me it works, and I have a lot of experience training aggressive players. That, and I've seen quite a few teams try to 48 a SG, for example, and their starting C fouls out in the 2nd quarter because they have it set on "Let them play."
I have never played anything but "Sit them."