Who has been pulled over for double towing illegally???

Well there is a post here talking about some fellow who was pulled over for not having USDOT numbers on his truck ,(in Iowa), so it could happen. Florida has roving Florida Dept. of Transportation cops, someone like that would be the most likely to snag you. They aren't rare, I see one a couple of times a month with a truck pulled over. They have portable scales.

No evidence but I suspect fines could be extreme and they would probably not allow you to continue. You have to get someone to come and tow one of the trailers.

Have you see it yourself, or just assuming that is what the single trailer means?

We see them coming from Alberta into BC double towing. They get pulled over and told to drop a trailer. The tell tail sign is the boat trailer or quad trailer on the side of the road at the pull out. The occasional overweight camper as well.

I have double towed a number of times but not in BC.

I'd love to help you out, but I double towed for several years and was never stopped. I pulled a swivel-wheel type trailer behind my 34' 5th wheel. I pulled through and in several states that don't allow double towing, including Illinois, several times.