New license plate for my TC.

Plates to be unobstructed
3.03 A number plate must be kept entirely unobstructed and free from dirt or foreign material, so that the numbers and letters on it may be plainly seen and read at all times and so that the numbers and letters may be accurately photographed using a speed monitoring device or traffic light safety device prescribed under section 83.1 of the Act.

That makes nearly all trailers illegal, certainly all fifth wheels. Make sure you stop frequently to remove bugs or snow/ice accumulation.