May not be true
Guy sees a queue at his banks ATM, decides to go across the road to 'another bank's' atm

Another bank's atm gives him double.
"Woohoo!" he thinks.
Does another transaction and withdraws everything he has in the account. Double again.
"Woohoo x2," he thinks. Then he thinks, "Aha!"

Walks across the road deposits the money his own bank.
Walks back across the road to dodgy atm, and does it all again... for the whole afternoon, until his bank closed for the day.

Walked away with 4,500. Would have been more, but you know those bloody queues in banks, never seem to have enough staff on when you need it.
( Sextant goes to him is emotionally erect, on this day, Thu 23 Jul 2009, 2:48, 5 replies)

If only the banks
could process transactions this quickly

Sadly, it's complete bullshit.
( chart cat has an itch, Thu 23 Jul 2009, 3:51, closed)

Yeah, probably bullshit
But not for the reason you say.

It is near instantaneous to deposit cash money to your account. The ATM of the other bank is withdrawing from your account.

It is perfectly feasible. All that is required, is a dodgy ATM, and a nearby branch of your bank for making an over the counter cash deposit. And the ability to stay quiet about the dodgy ATM rather than telling all and sundry.
( Sextant goes to him is emotionally erect, on this day, Thu 23 Jul 2009, 4:53, closed)

But
most accounts have a maximum amount which you can withdraw from an ATM in a day. I think mine's £300 or something.
( K2k6 has a proper job these days, Thu 23 Jul 2009, 8:23, closed)

Nah, it's littered with the usual apocryphal story inconsistencies
For a start, there's a cash withdrawal limit on UK bank accounts (usually around 500 quid per day, max). This is in place a) to stop wealthy individuals emptying cash machines on a whim; b) to prevent a large-scale run on the bank and c) to stop exactly this sort of fuckup from gifting any one person a large tax-free windfall. Banks could --if they so wished-- easily pursue and recover the funds, considering each transaction is meticulously logged from end to end. The reason why they usually don't bother to do so is the reputational damage of chasing their own mistake would be far higher than the cost of writing off the lost cash.

Secondly, as evidenced by other stories this week, any cash machine dispensing double would quickly develop a reputation and hence, a queue. That would seriously limit how much you could withdraw, even if no withdrawal limit existed on the account itself.

So really, it assumes that the person mentioned was the only chap using this benevolent ATM that day and he also had an account with no withdrawal limit. Both extremely unlikely, I think.
( chart cat has an itch, Thu 23 Jul 2009, 8:31, closed)

Accounts generally do have electronic withdrawal limits
But at least in Australia, these can be increased/decreased from the default upon request. My banks default is $800, but I've previously had my limit set at $2500 (I think they said $10k was the max), so if I found an ATM giving out double and had at least $2500 in the account, I could theoretically walk away with $5k in one transaction.
(teff, Thu 23 Jul 2009, 12:08, closed)