This is definitely a good word of warning, and I think it's 60% likely that when the first serious Bitcoin-shorting vehicle is introduced, there will be at least a 30% price drop in the first week (if 60% seems high, remember Bitcoin drops 30% lots of weeks).

I think Dogecoin is an even starker example of what's possible when you don't have a derivatives market.

Tangent: Wtf is up with the various types of derivatives markets? Why can't we just have asset markets and prediction markets?