Cross Border HD Coverage

[Yoyodyne]

I live in Southern Ontario and wish to purchase a Go Live 1535m HD Traffic. I was told to purchase this in Canada for the HD Traffic while in Canada, and to purchase a RDS-TMC Free Lifetime Live Traffic Receiver Car Charger for traveling in Michigan. It was my understanding that HD Traffic would only work in the country it was purchased. Now I'm hearing that a 1535m purchased in the US will also have HD Traffic available in Canada, but not visa versa. Has anyone heard of HD Traffic working in Canada with a US purchased 1535m?