Both banks(FED and ECB) use customer money to fund their bankster wallets. That's a risky scenario in itself.
Is it a ponzi scheme? That's debatable. It might be a sort of ponzi scheme, here's my logic:
1. Old people pay in the first money
2. Young people add more money because of the money the old people already put
3. Bank uses young people dollars to process old people refunds since they already spent the old people's cash.
4. So the result is young people paying for the old ones to get out at no profit. The only difference between that and Bernie Madoff is at least his ponzi scheme made some people money..
Just imagine what would happen if everyone went to the bank tomorrow and empty their accounts just to troll the bankers, actually don't do that, i have £2200 in my account that I need to pay rent with