interesting philosophy case study!!! tell me what you think!?

[anka]

Tom went to the ATM & requested $10 with a receipt. What he got was $1000 with a receipt for $10.
He checked his account online and found his account had been debited by only $10. He put the $ in a safe place expecting the bank to spot the mistake and ask for it back. But weeks passed and nobody called.
After 2 months Richard concluded that no one was going to ask for the $ soo he decided to go on a cruise to Bahamas

As he was purchasing the tickets he did feel a twinge of guilt. Wasn't this stealing? He quickly managed to convince himself it was no such thing. He had not taken the money;it had just been given to him. &he hadn't taken it from anyone else, so no one had been robbed. As for the bank, they would be insured against such eventualities.& it was their fault they had lost the $. They should have had safer systems. it wasnt theft, just best luck he had ever had

What do you think Tom should do? Is his thinking morally correct? Is this the banks mistake or is Tom stealing??