What the heck are you people talking about!? It shows that none of you have ever been in the military and have NO clue as to what you are talking about.
What it is is a warning abbreviation to the less than stellar but they left the I out NLOIFUS (No Loafing or I'll F*&^ yoU, Sh!7head). That kept private in sync that the 1SG is always watching.
Remember, I'm CARNAC and I know these things to be true.