it sounds a bit stupid to have the presence of a sticker be the be all and end all of that helmets validation.
In the UK there is some number on the inside which represents this (not the little british racing sticker as i understand it when i had my lessons there).
I've never ridden in the states, but I guess if i did I'd have to either buy a US helmet, or buy a doofy DOT sticker. How can you tell if it is just an added DOT sticker? Some other label inside?
'06 MV Agusta Brutale 910 || '03 MV Agusta F4 750 - Moto Corse Challenge 2 || '05 Yamaha FJR1300A || '04 Honda CBR600RR || '96 Honda XR250 || '90 Honda CBR250RR (MC22) || '89 Honda VT250 Spada
Tokyo, Japan