Saddly, I do not yet have a sgian dubh nor don't, and it is probably better to not have anything than to have something aughful. Kind of like McMurdo, I have a fold-up shoe horn and lint brush combination that fits well in a jacket pocket... just in case.

I think it might be a good idea for situations where you can not wear a sgian dubh, but I also like the idea of a flash drive, sgian dubh... just in case.