On ctrip, the cheapest fares seem to be available only as a mandatory "Promo Package" with the 30RMB hotel points.

On elong, when you select the cheap fares with a small notation "+30Up", a menu suddenly opens below with the choice of points or insurance, saying in Chinese "选择以下产品（可多选，至少选一项 . . ." It seems mandatory. But you can uncheck the box on the next page and the 30RMB apparently disappears. Maybe it comes back later in the booking process, I don't know. As I said, it's confusing and that's half the problem.