Paul Farace: A stolen camera ends up on some web-retail site or in a hock shop... purchased by some unknowing or thinking nudnik who then may and I repeat MAY post a picture... only to be confronted by the original owner.
It reminds me a friend of mine who had her very expensive camera stolen out of her car in Florida. The police gave her the usual "can't help you without a signed confession of the theif, etc." Well a few days later she sees her camera on a certain website (yea, it was that rare of a camera that it could be ID'd immediately)... she purchased it and arranged to pick it up from the "seller" who only lived a few miles away! She called the police again and they again gave her the run-around until she said she was going to meet them anyway and would be "armed." The detective got on the line immediately and they all went together to arrest the crook.
I do a lot of nude photography. The last thing I would want is for my spouse to enter my cameras serial number and then look up all the nudes I have shot. Also, when I sell my cameras, I wouldn't want the new owner to do a "check" on my history either. I think that there are serious violations of privacy laws going on with this.On the plus side, police wold be able to track pedophiles this way or even people who take pictures of their crimes such as sex crimes. Good way to collect evidence.
Also, I remember people posting or sharing their serial numbers right here on dpreview and on craigslist and kjiji to potential buyers. Maybe it's a great loss to anonymity when someone enters that serial number and finds out what you and your family look like and where you live? Who knows?