Errrr… I think that MAC can also be altered/spoofed.
And also new MACs could be available with new USB-wifi interfaces.
Also with a Virtual appliance, the guests OS have a new MAC assigned.
Etc… etc…
With respect to the IP:
There is no need always of a VLAN, there is some webpages that made reroute navigating trought them.
Inclusive, in many countries, our provider gives us a dinamic IP, that change over time.
HG!