I disagree. If the thief is dishonorable enough to steal this from somebody else who is already extending himself by offering him a service at no charge, I don't see how talking about a "finder's fee" is going to make that much of a difference. If a rapist feels entitled to rape you just because he happens upon an unhindered opportunity, is "how can we work this out" going to make much of a difference?
Coding error which sent bitcoins =/= rape. Equating the two makes no sense.
Waking up to find 512 btc in your account =/= stealing/thieving.
"You catch more flies with honey than with vinegar". A few kind words at the beginning could have gone a long way.