I would guess that the Chesterfield is the most prevalent of the Michigan "illegals," making them easy to get at affordable prices. From what I understand, after the club in the Detroit area was closed, the chips made their way to a club in Vegas owned by the same folks.

Here's a local article from New Baltimore, Michigan, placing the location of the club in Halfway, later East Detroit, now Eastpointe, rather than up in rural Chesterfield Township as many would believe. http://newbaltimore.patch.com/articles/chesterfield-long-rumored-to-have-hosted-illegal-casino. Chesterfield Township later became the headquarters for the Lionel corporation (the maker of trains). Eastpointe is home to Kelly services, the temp firm.