Well, maybe not... In order to skirt the laws (unsuccessfuly), it seems that prostitutes designate their payments as gifts, saying that the "gift" is a token of appreciation for their time. As such, if it really is a "gift," then according to the tax codes, it is NEVER taxable income, and the "gift giver" is only subject to paying a gift tax if the total annual "gift" exceeds $11,000 to this one individual. As such, I believe that there may be some validity to the assertion that it is not a commercial transaction, any more than when a boyfriend gives his girlfriend a diamond pendant or earrings, and she thanks him in a private and personal manner. It could be considered a gift in the truest sense of the word. Technically, the prostitute is not forced or in any way compelled to provide the "gift giver" with sex.
Mark
I only go by what I read, no personal experience, but I think that while this may be true of an "escort" (someone to have hang on your arm, dine with you, keep you company, show you around, show you a good time, etc.), a "prostitute" will negotiate the price for certain acts ahead of time (negotiate for the amount of time together and then so much money for each sex act). This includes massage parlors (different prices depending on what exactly is massaged).