There are _no_ people who will take up an interest rate over 15% unless they either (a)have no choice because they're already fucked or (b)have no understanding of the situation.

Sure there are. Never seen goods offered for half-price or less? It could be the cheapest way to buy something if you manage to pay it off in a year.

But of course people are being ripped off, but you're just assuming they don't know it. It's like smoking. Plenty of smart people smoke, even though they know it's going to kill half of those that do. Should the government pass a law to stop them smoking?