I was on an LX euro zone flight once where 2 pax had been upgraded to C but they also didn't have enough meals. In total there were 3 pax in C. Before departure the MdC inquired with the gate agent which passengers were upgraded. She came back an said I had been upgraded !
I was the only C pax but was denied the meal because the gate agent was too stupid to look it up correctly.
As the food is rubbish anyway I only protested instead of pushing the issue further.