in all seriousness, an errors that huge WILL get caught. It will get flagged by so many agencies its not funny, from the GOVT to the bank, to FBI, etc.

$1000 they can POSSIBLY miss, anything over that, they will catch it eventually.

If you took 100million, you would have every bounty hunter, newsagency, govt official after you , you would not get very far. Even though its their error, most banks have user agreements that will supercede any "its a mistake its mine"

they WILL get their money, one way or another.