If you have a working VPN, when you turn the VPN connection on, it doesn't matter where you are at, once turned on you are "virtually" sitting at a computer wherever that VPN server is located. For example, if I'm in Belize and start my VPN connection to a VPN server that is located in the U.S., then I am "virtually" sitting in the U.S.
So if Magic only works for calls in the U.S. and Cananda and I'm on a VPN server located in the U.S. then it doesn't matter where I am physically located once the VPN connection is started, Japan, China, Cuba, etc... once the VPN connection is started I'm "virtually" located where ever that VPN server is.
Make sense?