I have two servers with RRaS service installed.
Virtual VPN Adapter always uses MAC=00:53:45:00:00:00, so i have two servers with same MAC. I can switch off identification by MAC, but in this case when i reinstall office computer under another network name i will have two computers in assets -- one with old name and one with new. So i think it is better not to use information related to virtual network adapters in assets http://weblogs.sqlteam.com/mladenp/archive/2010/11/04/find-only-physical-network-adapters-with-wmi-win32_networkadapter-class.aspx