Fortunately for central banks, the hoarding of cash creates a host of other costs.
Part of it is storage and transport, though they are not the biggest problems. A withdrawal of a large amount of cash in one swoop would keep transport costs low, while the high value of the largest denominations of euro and Swiss franc notes mean that large amounts can be stored in small volumes.
Even when the ECB stops issuing the €500 note in 2018 and banks will have to use the smaller denomination €200 notes, there is enough space in vaults, according to private bankers.
Bank robbers, earthquakes and other unforeseen disasters, on the other hand, are a problem. Or rather, the delicate issue of finding an insurer willing to take on those risks while charging a reasonable fee.
"No one stores cash for large amounts of time. At the moment, cash comes in and then goes out quickly to ATMs," said a German banker, who has looked into the costs of switching to bank notes. The banker estimated that the insurance cost would probably be between 0.5 per cent to 1 per cent of the value of the banknotes being stored.
That would be higher than the ECB's negative rate, but in line with Switzerland's minus 0.75 per cent, which is one of the lowest in the world.