WITH ALL THE MONEY THEY’RE PRINTING, you’d think there’d be plenty of cash out there. But actually, banks don’t keep much on hand any more — customers don’t want all that much, and there’s always the risk of robbery. I was talking to some tellers at my bank and was astounded at how little they keep. They said it hardly ever creates a problem because they can order it delivered on pretty short notice, and not that many people want to make big cash withdrawals. But it would be easy to create a bank run that would strip banks of cash when supplies are that thin. If I were a banker, I think I’d up my cash-on-hand in response to stories like this.