Perhaps the players should have thought about that before making their political statement. If you want to be your own country, then be your own country, and accept all the responsibility that comes with that - like negotiating visitation and immigration treaties with sovereign nations.
Official acceptance of such divisionalism/exceptionalism tells me: America was a great idea, but didn't last.
It's dead, Jim. Toast.
Stick a fork in it.
It's gone.
By accepting US or Canadian Passports and acquiescing to this solution would essentially have ceded the issue of sovereign recognition on a very significant level.
They are NOT part of the US or Canada, they have their own sovereign nation and should be recognized and accepted as such!