My experience when crossing the border from US to Canada is they really care about banned produce and meats. However they do look at your license plates. I had temp tags once since the camper was brand new. They did ask to look at the registration and checked to make sure I really owned it. Luckily I had brought with me, all the paperwork from the sale and registration.
Driving throughout Alberta and BC however, we hardly ever saw RCMP and certainly were never bothered by law enforcement in the thousands of miles I've driven over the years.
I should mention however, that if they do happen to check your weights, unlike here in America, they look at the yellow payload sticker as a reference. And if you're overweight they can impound your rig. I was advised of this by a Canadian, but I have nothing other hearsay.
In the US, what I've heard from forum members, is that if there's a checkpoint they weigh your rear axle and compare that to the load ratings of your rear tires.
That's why you can register a class III 14k lb GVWR truck as a 15k or 16k truck in California.
Grit dog wrote:
Heck, I drove through BC twice the same spring a few years ago, moving to AK. Once with a brand new F250, not in my name, paper tag stuck in the back window, loaded to the gills, rear suspension sagging pulling a trailer with a permanent license plate off of a different trailer I'd owned in the past in a different state. Even chatted with RCMP in the middle of nowhere. Pulled over to take a leak and he stopped to see if I was "ok." The following month, I had a 4500lb camper on the back of a 2500 with expired tags (just expired and didn't renew as I was moving to AK and not about to buy new tags just to buy new tags 2 weeks later) pulling a heavy trailer which I'd just bought and not yet registered, sporting the plate off my boat trailer that was left in the shop in WA.
Neither the CDN or US border cared.
Don't worry about what someone says about a place 3000miles from your home.