At the end of each class, about once a month one of my instructors gives out stripes. There is one well known guy that always talks about himself getting promoted. He is extremely lazy and everyone who trains with him knows it.
Anyway one day one of our instructors calls him to the front. He walks up, proud and cocky with a big smile on his face. The instructor then tells him to do 50 pushups and get back in line! For not having his belt tied while bowing. Our school is not strict at all, in fact bowing/belts isn't really enforced at all usually, but obviously if you want to make yourself out to be some kind of BJJ hero you are going to be treated like one. It was awesome! To this day he doesn't have so much as a stripe. Not that stripes/belts are the most important thing, but to be honest he hasn't improved much since day one.