Just to add, the people I train have NEVER had a training injury.
Are you talking about the kids only? Because ALL powerlifters have injuries, ALL athletes have injuries. It's simply unavoidable. What competitive powerlifter hasn't had multiple serious injuries? Many of them can't even squat their body weight without being in a suit or briefs and loaded on narcotics and lathered with horse liniment.
Don't you think the kid was pushing his knees too far out?
I don't know, but I sort of feel that using bands may be too advanced for that kid, like for many others that use them. Same with doing these advanced "conjugate" programs. Should be doing technique work and linear programs for longer before starting a bunch of advanced shit. JMO.