I may be missing something but it seemed to me VRBO was already being pretty aggressive about preventing outside contact. I used them for a rental in FL in January, and there were documents that needed to be sent to the owner re condo board approval of the rental. For some reason VRBO was garbling the document when sent through their system. It took some subterfuge to get him my email address so we could communicate directly. They were stripping email addresses from anything that went through them.