What crime?

I saw this on a new comedy show about two bungling burglars. I thought I would throw it out to the legal minds here, to stew over a glass of beer:30: 

One guy says, with a puzzled look on his face "If a man goes to a prostitute, and skips out with paying her, would that be rape?"
His buddy relies "Nah - that would be like shoplifting".

I know the courts cannot enforce what is in essence an illegal act, but let us suppose that prostitution is legal (and it may be very well so in Mexico), what could this deadbeat diddler be charged if he was arrested?

The same crime that anyone gets charged with that doesn't pay a service provider for services rendered. Although since so "goods" are involved it would probably be more of a small claims court situation and not an actual crime.