Yes I am often asked when I approach the F/J counters in Singaproe, "What class am you travelling in today, sir?"
When I answer, economy... they then say, "Oh, you have to go over there...".
Well, they do have a point, because they didn't ask for my status.. but I say, it's okay, this line is empty anyway.. the agent then tries to block my entry until she sees my MPC baggage tag. Then she relents.
I guess it's a mouthful to ask: "Are you a Oneworld emerald, sapphire or Marco Polo Club member or travelling in Business or First class today?"
It is faster to just ask when class are you travelling in...