Nothing is more funny to a bull than the OKcoin bear that got
margin called today for 31,000 BTC/3 million dollars. His wife is gonna kill him.
No kidding, this guy was slaughtered on the alter of doom and it was a major shot across the bow of the bearmobile. If it can happen to this guy, it could happen to anyone.

His mistake was not the shorting, it was the insane leverage he used. Also you don't know how often it worked for him... he might be well in the green in aggregate.
This can happen to
anyone with highly leveraged positions, yes. Not just bears.