My Academic Minute airs today on NPR. (It's not posted to the site yet, but it's on the radio today.)

CORRECTION: I said in the recording that Robinhood limited trading so that users couldn't take profits. In fact they continued to allow long sales.

Because they didn't allow long purchases, they were still preventing their users from benefiting from the price rise. So what I said leans in the right direction, but I overstated the case.