Been a while since I decided to toy with one of these. Wonder if I'll get anything fun back...
The best part is that I didn't send the passport to "the guy wanting to give me money". I put it in the form that the supposed HSBC sent me, then the original email address sent it back to me angry and accusing me of trying to scam him out of his money. The whole thing was just a real fun time, honestly.
Whilst I wait to see, as a fun fact for you, I once had one of these idiots threaten to call the Metropolitan Police on me. This was after, among other things, I sent him "my passport", quote-unquote, which was just Jorgi Costava's fake passport from Papers, Please. Man, that was a heck of a ride.