I would say I'm taking a fairly big risk right now as it is. I have no guarantee that BTSX will be as successful as I think it will, and also no guarantee the price won't dip below the margin call before it rises greatly. Also by keeping my BTSX tied as collateral for the shorts, I'm risking opportunity cost from being able to trade elsewhere and in other coins. Based on that, I definitely wouldn't call a long-term short a "free lunch".