I am a VIP member at Midwest Gun and Range. I shoot there at least once a week and I have never in the last two years witnessed anybody allowed to be unsupervised with a full auto rental. They always have an employee with the weapon.
They might have gotten more strict about the policy but we were shown proper operation and watched for 1 magazine each (my brother and I would share a lane). After that, we were on our own. If they're more strict about the policy, I'd be perfectly fine with that but I know what happened when we rented them.