What a totally hare-brained idea IMHO!
This needs stamping out before it affects us all. Mind you if it shut drivers up about road tax it might be worth considering as our VED rate would be £0. Having said that, the fact other road users pay road tax doesn't stop those of such a nature from abusing other drivers anyway. Cyclists are just a target for the illiterate, impatient and ill-informed.
As you were!