You're missing the point, massively.
Sponsors will need to see balance sheets to prove that the team is a good choice financially speaking.
If City have built their reputation by using fake puppet companies, that will have a knock on effect [Fake company A invests a million, real company A see's that and is tricked into thinking "we could offer more for a more prompinent placement" etc] Then down the road, new sponsors will see their *true* value, which can hamper further sponsorship deals.
It's not like these companies will be happy knowing they were conned, and then sponsor them again. Hell If City are found guilty, I wouldn't be surprised if the genuine companies that sponsor them sue them too, gaining investment through false financial records is very illegal and alot of money has changed hands