I've taken part in firearms training involving "sim-munitions" fired from real guns. Before entering the training area, each person was checked at a gateway area for ammo, by pat down and by metal detector. His firearm was checked by a line of three inspectors, he would pass through the gate, be handed his handgun and a mag of simunition (which was loaded under the supervision of three sets of eyes)
Instructor has never had an accident
One full mag of Simunitions?
Personally, if I’m training for combat scenarios, I’d rather have a full loadout.