I extend politeness to anyone I meet and can surely expect the same from others, including colleagues but also estrangers and even my wife. Whether money exchanges hands is completely irrelevant.
Flying in Spain is a pleasure because you are always made to feel welcome and a jump seat request is often answered with 'you are in your own home' Common courtesy means that you will stand at the back of the queue and allow all passengers to board and disembark first. You create no disruption and the extra cost to the co is almost nil. Those of you that knock this system feel free to throw stones at your own roof but please do not complain when it rains.
Do teachers in private schools pay full fees for their kids? does a ford employee pay the full price for a new focus? Does a state agent buy the most overpriced house in the books? Is that comparable to a Judge knowingly giving a lenient sentence or a policeman allowing his colleague to rob a bank, hardly....