Back in the day before digital cameras, I also used to take photos on film, but I didn't have my own darkroom. Same thing.
If you use IPv6, the attacker may not even have to break into the access point to find your MAC address, because the IPv6 stateless autoconfiguration mechanism will helpfully embed your complete MAC address in your IPv6 address. Such is progress...
It seems the only way to administer XenServer is from Windows - is this correct?