Originally Posted by joejones

Fifth freedom tags (country B to country C) often have local traffic rights, but tags within a foreign country never do.



While we're fantasizing, one obvious alternative would be for the US and Canada to adopt a Schengen-like system so that there is no passport control between them at all. That would be amazingly good for business in general, not just for travel. Likelihood low, though, especially given all the security paranoia in the US.