Originally Posted by
Dubai Stu
Given how closely the US and Canadian phone systems are interconnected things can be different, but my experience is that your carrier gets a great deal less information when you are roaming abroad. Unauthorized device swaps often coast. I know of people who have shoved their iPhone International SIMs into hotspots on foreign shores and gotten away with it. I'm too much of a coward to try that one.
I think that is more of an issue of "suitable" APN's while roaming. A tethering APN will nail you regardless.
When a conventional roaming session is initiated the only information relayed back to the home network is the IMSI (not the IMEI) and the phone number for authorization.
The Canadian carriers do roaming a little differently though because they don't use Syniverse for US roaming and calls and data sessions are initiated directly.