iBee-yotch
My policy is to return items to the people who've lost them, no matter how appealing the find. For this service, I think one person in 15 years has given me five dollars. (!) When people return my things I always give them some reward, based on how costly and annoying it would have been to replace the item.
Last night I found an iPhone and was looking for any clue as to who owned it when I got this delightful msg.

Umm. you're welcome biz-natch.
True to form when the combative, foul-mouthed owner claimed her phone today she gave me a five dollar gift-card to Starbucks (I don't drink coffee), and a paperback on surviving an Alien Abduction. Hey thanks!
I saved her $500 and she offers a one percent reward! Thanks a lot Denise Johnson of Houston, you cheap *****. I'm done returning items. People don't deserve their stuff back.

Are you sure that wasn't my iPhone you picked up? The passive/aggressive thing to do would be to use it to email death threats to public officials; then download gigabytes of documents on nuclear bomb manufacturing, child pron and Metallica mp3s, before kindly handing it back to her (a taking her 5 dollar reward).
Gomez 03 Jan 2008