Cathay isn't always the best airline but at least their staff (or the ones I've encountered) are smart, even if not always the most cheerful:
One of the staff managing boarding at the gate was holding a boarding sign for "First Class, Business Class, Marco Polo members". I thought that was weird, because usually only MP Silver and up board with business and first class. My Green tier is actually useless if you hold a Premium Economy ticket as it only allows Economy ticket holders to board in the Premium line
I asked her if all MP members were boarding now, she said yes and sent me to the business line. I thought that was weird but had time to burn even if it turned out to be a mistake, so did so.
The woman scanning my ticket told me I shouldn't be in the business line, as the Premium line was on the other side; I said her colleague had told me to be in this line, and she just got on with it and didn't bother arguing, likely because arguing would have slowed down boarding further.