Thanks again for the insight. While I am actually aware of why the dirk and sgian dubh were originally worn on the right side, I was just wondering if some rule of etiquette required it.
As it seems it's just convention (and the assumption that the wearer is right-handed), I'll continue to wear the sgian in my left sock. Should I ever get a dirk, well, I'll make up my mind about that then. As long as I know that I'm not inadvertently being rude, whether anyone else understands why I would wear it on the left means little to me.