[Bilbo Baggins]

The last I checked, prostitution was still illegal.

Then arrest them on that charge and let the courts decide.

Since when was it illegal for someone to call another person or some business?

[Cold Heat]

Phones are regulated by the same govt. that called prostitution a crime.

Selling services to a criminal enterprise, once one is warned about it, is something that they can indeed regulate under law.

[Cold Heat]

BTW, they can and often do move the stuff offshore, but some recent legislation has curtailed that as well.