Can I stick a label on a P2 card? Is it going to fry up or cause some other kind of problem in the camera? I'm talking about a P-Touch sticky-label type thing...
Oh, no, the glue from the label will dissolve the thin anti-cosmic radiation shield, which will erase all your pictures, including those on your computer at home and drink all your beer from the fridge.
On the serious side, the only problem would be the thickness of the paper. If you are confident that the card will go in/out of the slot easy and will not get jammed because of the label there's absolutely no problem. Another option is to use the specially provided labeling space.