Seriously, it's not like someone is randomly depositing money into stranger's accounts. It's an error and they will most likely catch it, but don't spend it since they will make you give the money back if/when they do.
i work for a credit union and it happens often when a teller puts a deposit into the incorrect account. we call it a "mis-deposit". we find out when the person whose account it was supposed to go into calls the customer service line and says "I made a $1500 deposit on 2/23 and it's not in my account". then the customer service rep finds the teller who did it, find out account that it did go into, then debit that account and credit the correct account. and it doesn't matter if the incorrect account still has the $1500 or not - hell if that account is at $0 then it will go to -$1500.00 with the swiftness and you end up owing that bank $1500.00 which 99.9% you no longer have cause it got wasted on kicks, polos, 501's and whatever young people are buying these days
edit: swizzc -a bank can re-open a closed account and still debit the amount -