If that's the case, I hope the RIAA will fail in their quest... because if they succeed, churches (or other religious establishments) will follow suit and gang up with the hotel industry and the catering service business, to sue casual sex couples for their lost of business cuz it obvious the couples in question are not going to get married.
Since there is no doubt alot of benefits are exchanged with no money needed to be involved as far as casual sex is concerned, you've got a commercial activity right there, as both parties derived LOTS of benefit from it.