Far greater chance of being clobbered by an under 25 year old who's brain has failed... However, I agree Keith, I think all vehicles should have a compulsory MoT test every year Including trailers...
Some of the trailers I prohibit are an absolute disgrace. We recently had one come adrift cross the road and hit a motorcycle. The rider will never be the same even if he survives. You just can't trust owners to ensure their vehicles are safe.