That would be swell, except for cases where the "risks" involve losses greater than the ready assets of the financial institution involved.
You know what, then financial institutions shouldn’t do the deal, huh? That’s one reason why I don’t use a margin account. I’m in the market in 7 figures to the right of the decimal point not including commas, OK? And I have an MBA and still I don’t play puts and calls (or commodities in a big way). I like to sleep at night.