The banks store money. If you want your money, you get it from the bank. If all that money disappears, then there is less money. Supply and demand says that if there is less of something, it is worth more.
All of a sudden the banks close. The EFTPOS doesn't work. The fruit shop owner still needs to buy bread, petrol etc. so he needs money. Only you, me and D12 have cash, so we can dictate the price. Then, we just need to get home without being mugged ....
