It's interesting, because what we call sharing is really preventing sharing. If you're using a certain frequency on one side of the border, you have to avoid that frequency close to the border on the other side. So as we do when we share within Canada, we make sure the frequency doesn't get re-used within a distance that would cause interference to users.
For example, we have channel 4--channel 9 here in Ottawa. You're not going to use those same channels within a few hundred kilometres of Ottawa.
It's the same thing with the U.S. We've negotiated what we call the allotment plan, which means every frequency is known, whether it's a U.S. frequency or a Canadian frequency, within 300 to 400 kilometres of the border.