It doesn't even need exotic trades. If you're doing margin trading on a stock for which there is a sudden dip in stock price (as in previous flash crashes), the

It doesn't even need exotic trades. If you're doing margin trading on a stock for which there is a sudden dip in stock price (as in previous flash crashes), then there will be a margin call and from the customer's perspective, all their money and shares will evaporate. I wonder how Robinhood will handle it when it happens.