To dirk or not to dirk?

[David Thorpe]

I don't wear a sgian dubh, either for the very same reasoning (kilts as part of functional dress rather than costume).

I can recall any number of instances where my sgian dubh came in very handy. (as in Tobus' example). It is not the least bit "costumy", but rather a common element of THCD. I can also think of many other parts of THCD which could hardly be considered "functional dress". No matter. Wear one or don't.