Other than a few, particularly puritan jurisdictions, it's been my experience in the US that the anti-prostitution laws are almost exclusively aimed at "street hookers" - e.g. those most in need of help, not harassment! (To be clear: I mean in enforcement, not in the laws themselves.)
I'm all for legalizing and "licensing" prostitution. But key is keeping the "rough trade" out of it... if someone's doing it because they want to... fine. If they're being forced or coerced, that's another matter.