Yes, in 2 ways: they may not have a special meal in the higher class, and skip you for another candidate to op-up. And, more importantly, they may not have an extra regular meal in the lower class -- for the person who will be taking your freed seat -- and not op-up you even if you insist that you are happy to have no food for yourself. In general, special meal = no automatic opup. Of course human intervention can still get you an opup, but special meal cuts your chances by an order of magnitude.