I don't display mine because there is nowhere good to position it on the 999. Anyway after having two stolen - one hacksawed off on my 996 leaving scratches on the frame - I carry the disk in a small wallet with my plastic drivers licence, insurance slip, RAC card and DSC membership card.

Hopefully no-one would be that pedantic if I got stopped - so there goes that idea then. 10-1 I get pulled this weekend.