I asked an adjacent question to a broker friend who flatly replied: "Not interested in being served a Wells Notice."

Which more or less answered the question for me, even if he was being a bit hyperbolic.

Why would anyone let you do that? What's their incentive? I assume you're offering something as security for that money (shares?) but why would people complicate an already risky proposition further or go into the lending business that they're not in?