ID passengers are kind of odd. I presume they are on standby. Even without op-up, an ID90 can still pay 10% of J to get in a J cabin. So I am not too sure exactly what that means. On the other hand, CX may try to discourage op-ups in order to get people to pay J or use miles. That is just my guess.

I always thought that the ISM has the passengers' information on the BPs. So they will likely know op-ups. The ISM told me that she had information on op-ups, mileage upgrades (if I heard correctly), specific arrangements, etc., but has no idea of the booking classes.