It's one thing if they choose to hurt themselves, but what about the risk it puts everyone else at in the gym when weights go flying and those balls shoot out and hit somebody else.
In general I don't pay attention to what people do or don't do, but this crap puts people around them at risk of injury
Never ceases to amaze me how full retard some people allow themselves to get.
Any trainer who advocates any of those training methods should have all credentials revoked immediately by the 'common sense police' and be blacklisted for life and sent to a small inhospitable desert island.