It is a perplexing question. I don't really see how they exist without the threat of violence, either.

But that leads me more to the opinion that they probably don't exist to the point people still think they do.

Although I guess you could look at it from this point of view: Their reputation would probably be sufficient to keep the majority of people in line.

But, yeah, it is an interesting question: Why would someone who decides their gonna be a bookie in Chicago land kick up without the threat of violence?