That's not quite my point - you asked where would you mount a rear plate on a tractor, to which I answered that there are lots of places. If you're talking about the fact that plates can be obscured by large trailers etc then local laws will dictate that there is a plate on the trailer. I guess plates covered by attachments (ploughs etc) are a slightly different case and may obscure the plate.

> It's not entirely uncommon for tractors to be pulling even bigger things which would cover the plates.

They're not at a high risk of speeding at the same time as that.