I'm pretty sure Non Merci is referring to those rude and arrogant people who simply walk beside the line and proceed directly to the head of the queue.

I get so enraged when I, having arrived at the airport on time as required, am punished by having to wait for the morons who arrive late and decide that they are too important (too stupid!) to stand in line to check in.

I remind myself that these idiots are the same morons who miss their departing flights from Paris and Lobdon because they are too poorly educated to arrive at the airport on time.