There seems to be some confusion, on BOTH sides of the border on this one.
First off, just because *one* border agent let something pass, or just didn’t catch it, means NOTHING if a different agent at a later date looks at it.
Secondly, the issue with crossing the border is two-fold, 1) licensing, and, 2) ownership.
1) Licensing, if that is a temporary item, can be a “license” or a “permit”. A “permit” is rarely valid or honoured beyond the borders of the State or Province that issued it. That is why Ontario changed from a ‘trip permit’ to a 10 day license.
2) Ownership, to enter Canada with a vehicle it is considered personal effects, no different than a suitcase of clothes. This is why you can’t drive someone else’s vehicle across the border without very specific documentation. If you have yet to receive a “title” from the DMV then you likely don’t have sufficient proof that you own the RV to cross the border with it. One interesting difference is truck campers. In Ontario, and I believe the rest of Canada too, they are not considered to be a separate vehicle and do not require plates or ownership documents.
