Is there proof of this? This gets repeated a lot and the best "proof" I've seen was a wsb post claiming they got sold "without [their] permission", but stopped short of saying whether they were using margin or not.
One piece of the "Robinhood Abstraction" that is popping up a lot right now is that the fact that a large majority would have been using margin, but not known it.
Much of the nice and fast experience that Robinhood offers ("Just signed up? You can start trading!", "Initiated a transfer? Start trading now!", "Just sold something? Rebuy something else immediately!") are all powered by the fact that these are all technical using margin.
If you use the "instant deposit" feature (its ON by default) on Robinhood, you are using margin. Its one of the weird things people never really though about.
