Big Cliff has it right.
Believe me because I got caught and it wasn't nice. The MOT and Canada customs aren't stupid, They've heard it all and know all. At one time the two weren't linked together, but now they closed the door on the tax dodgers. A friend told me that just pay the tax on the trailer and that was it, so I did . WRONG! A few years later I received a letter They had contacted the seller and asked him if he sold his boat package and asked how much he sold it for . If you want to save a little on the tax, do the bill & story straight thing and your the bills better jive.
But remember think about what Big Cliff said. Don't forget you have the bill and what you paid the tax on. The loops are smaller
Good luck on your saving, I like to save a few bucks like the next guy, but be carefull.