Safe(ish) as in the worst that can happen is that you never see your money again. Though the risk of that happening is far higher than with other investments.
Selling a call option is especially dangerous, because you could be obliged to buy the shares at whatever price they happen to be at the time, and the sky is not the limit for that.
The risk to hedge funds using call options to cover their losses is counterparty risk - that the person who sold them the call option can't afford to buy the shares needed to close the option, and goes bankrupt. In a situation like this, that is a very real risk.
Biting the hand that feeds IT
