Slim-Slag,
The establishement of two way communication is permission, my concern was that you were implying that the VFR pilot could just fly through without communication being established.
The key is that the controller has to answer you using your call sign, if he says acft calling XYZ approach stand by that is not establishing two way communication.
It is far safer to contact ATC and let us know that you are out there than to assume that we see you!
Mike
NATCA FWA