re: BOIL has become predictable

I'm pretty careful. You have it about right. There is risk, but again the risk is like $2,100 for every long synthetic, or what is sometimes called a bull risk reversal. Buy a call, sell a put is the equivalent of a long stock position at a cost of under $100 instead of $2,100 at entry. Maximum loss in both cases is about the same, and maximum loss is unlikely.