What ho, Mr. Free Market, from nearby Des Plaines, IL. You may have noticed the world's largest parking garage adjacent to the Hilton. Many years ago security cameras were installed. From those on the top level, one could look into rooms at the Hilton, wherein one could observe young ladies of the evening applying their free market skills with clients they met in the hotel bars. Beer, pizza and porn on the midnight shift.
Need I say that the garage was operated by the City of Chicago? Cheers!