Support:

I was thinking that in the CP for Vendor Options, if we had a default Country this would go a long ways to solving this problem. Even in Canada, 90% of the vendors are typically in Canada so this would be useful to Canadian users as well.

Also the likelihood of entering BC for a US customer or visa versa is slim. In other apps I've seen North American validation include a combined approach including all states and provinces so that you weren't forced to pick a country first.