Strange, one of the crossings I referred to was in an Enterprise rental when my coach broke down in WV.
When I told the rental agent I was driving it to Ontario they just made a note in the computer saying it was going to Canada so it wouldn't set off any alarm bells leaving the country. All the CBSA folks asked was if I had the rental contract with me, they didn't even want to read it, just that I had it.
One thing I do know is that a US plated vehicle is a "personal possession" and so you need the permission of the owner to bring it into Canada. In the case of the rental maybe that's what they put into the computer?
In cases where I've driven privately-owned vehicles across the border they owner had given me a signed letter saying I could cross with their vehicle.
It woul be interesting to see what the official word is.
