As Griffmuss says, at the MGP they do insist you use the numbers supplied. Some people have whinged but at the end if you don't fit them you don't go through scrutineering. No doubt all the big boys at the TT are used to insisting their expensive paint schemes and sponsors logos aren't altered but as thewitch quite rightly says, if somebody needs to be black flagged it's important they can identify the bike easily!

Thye ACU and MMCC seem to be quite keen on safety this year. Maybe they should consider this safety move too, even if it doesn't only affect holiday racers.