Without sounding too cynical, I can’t imagine a complete stranger safely returning an expensive piece of equipment like a dSLR if you accidently left it behind. Not to say there are no more honorable people left in the world but for those few that would have intentions of contacting the owner, how would they even know who to reach?
After reading about this neat idea of dog-tagging your camera, I visited my nearest Petco store to create a personalized tag that bared the vital facts to identify my camera: name, website and phone number. The whole process took 5 minutes to complete and the entertaining part is that you operate and oversee the whole procedure yourself from this vending-like-machine all for just $8.
Hopefully the tag will never serve its true purpose but it certainly adds a touch of personality to something you truly call yours.