Her biggest issue is not the prostitution charge but, as one other poster noted, tax evasion.  The Feds do not like people who fail to report their income; I'd bet NY State's tax folks feel the same way.

...they have to respond.  On the surface, it seems like a weak case, but scare tactics so often work.  In our puritanical nation, prostitution will be bad until we can all pretend it doesn't exist anymore.