...............if that the case it makes no sense when they have no rounds left in their gun. I don't know why they do it but it sure looks dumb..... I don't see everyone do it, just some. take a look at this guy doing if you don't what I'm talking about... skip to about 1:10
LOL, checking your six for danger, under certain circumstances is a wise practice whether your gun (which should be in the process of being reloaded) is empty or not. Or even if you don't have a gun.
Just my thoughts on the matter.