If money that wasn't mine mistakenly entered my account and I was not contacted after 24hrs, I would go to the bank and report it then ask for a copy of a mail to the regional head and a signed letter stating clearly what happened. It wouldn't even cross my mind to announce it on social media but maybe he had exhausted all other private options.That was exactly what I did last year when it happened.I still have my copy of that letter.Stamped and signed.Maybe not the best move,I must say.
What I love about this though is his opportunistic mindset.He would have been caught if he had kept the money but publicly returning it would most definitely earn him very good rewards in some way. Sharp guy!