I have my DM tag on my carry on bag. But, I have it in such a way that I can tuck it into a pocket of the bag if I don't want it hanging out. I feel a little strange having it out. Maybe it is a midwestern sort of thing.
On a side note, a few weeks ago in the Delta club I saw a guy with a DYKWIA bag tag. I loved it. I may want to get one made.