Hard to place this one in a specific sub-forum, left to discretion of moderators.
http://soldiersystems.net/2012/11/08...ful-out-there/
http://www.ar-15.co/threads/70875-Instructor-shoots-AI
Many things can be said. My own prospective, as a student: never rely on others being safe. Vet your instructors. Watch what everybody does, and be alert. I bought individual body armor after my third carbine class. I wear it 100% during low light/no light classes, about between 66 and 100% during rifle classes depending on my perception of class safety, and occasionally during pistol classes.