Here's one for you:
The DI's weren't permitted to hit a problem recruit. But they got around that pesky regulation by lining everybody up in front of their racks, at attention. Then the Senior DI would walk up the squad bay and give everybody, one-by-one, a punch in the stomach. If you were a squared-away private, you got a powder-puff hit that hardly hurt at all. But when he got to the fuck-ups, BAM!
The logic was, according to the SDI, "If one of you maggots reported me for hitting you, I'd be in trouble. But if all or you reported me hitting you, nobody'd believe it."