Let's say you push product on a specific corner. Another cat rolls up trying to snatch your customers. That's bad for business, and it's going to be handled. A cat could come in from outta town trying to set up a lil shop in your area. If people are allowed to do this willy nilly, that could easily spell the end of your business. G's check in to let the hometown cats know they're in town, so they don't find out on their own and have to wonder if these dudes are up to funny business. This Tekashi guy is required to do this only because he claims to be a gangster. If he didn't project this image, he wouldn't have to check in.
I'm not saying this is right or wrong... just answering the question.
It would be smart of him to abide by the rules. Call street rules stupid and disregard them at your own peril.