Firing from the hip in full-auto is what heroes and villains do very often in bad action movies. This is perhaps the explanation why some people think that weapons like AK-47 were designed to be spray bullets from the hip. They weren't. Firing from the hip is a supremely bad idea.

First of all, an infantryman just doesn't carry enough ammunition to fill the air with lead by firing without aiming. There are support weapons for doing that.

Second, he would have to expose his whole torso while firing. This is an extremely bad idea. You really don't want to expose anything more than absolutely necessary when on a battlefield.

Third, most weapons have a shoulder stock for bracing it against the body to give stability when firing. Movie ammo doesn't have the recoil of real stuff, which makes the weapon easier to hold with just hands.

Fourth, weapons have sights for aiming. Most people do not have an eye in their navel. Even a burst is more effective when fired towards a target.

Fifth, most sensible styles of carrying the weapon make it easier to raise the weapon to the shoulder than to lower it to the hip.

So, boys and girls, fire from the shoulder, not the hip.