I should point out that if a Canadian station chose to attempt to "border blast" to the US, I find it near-impossible that the FCC would act (or care). You can bet your bums, however, that the CRTC would strip a "border blaster"'s license faster than you can say "back bacon".
Didn't CKLW (near Detroit) do that for years?
Canada has some interesting trade protection laws. I know of one popular 90's rock group that refused to play there because of the insane costs involved. Another smaller, local rock group in the late 90's (comprised of two Canadians with dual citizenship) refused to play there for the same reason. Because of the restrictive rules, you didn't make any money.
It was an eye opener for me. I'd always thought that there was such a thing as free trade, and all that. I guess it's not so free in some fields....