Expiry day is going to be very interesting then. I had no idea their volatility rules would apply to expiring contracts too, that's insane. Why would anyone want to trade that instrument?
This is how all future contracts work. There are daily limits that lock the contracts from trading. Interestingly enough these contracts seem to have very high margin requirements and lock limits. I also find the discussion about "shorting" to be interesting. All futures contracts have 2 position - a long and a short. The number of "shorts" is identical to the number of longs, unless I am misinterpreting the was these contracts are set up.
I wish I know :). Its not really a derivative if volatility is capped while the underlying is free to move around.