my puzzling question

Why do students who receive some kind of funding/aide from either the school or the government, go to class for only a few days then drop or just fail and hardly ever get caught? It's not fair. I had a friend who did just the opposite but when her G.P.A dropped a little, the government made her pay back a portion of her aide. She was going to class and trying to succeed but those who are not doing that are getting away with it.