I agree that the phenomenon is more common, but I believe it is less cunning than you make it out to be. My explanation is that the mechanism for regulating one's behavior has shifted from an internal one, based on a sense of what is appropriate (lagom, for Swedish-speakers), to an external one, based on what others will tolerate or fail to challenge. The bad behavior persists because it gets rewarding results for the actor.

This is why I get so angry with those who do not challenge others who are out of line, for they are reinforcing others' bad behavior through good old operant conditioning. In fact, I take umbrage at those who go out of their way to avoid a situation in which the possibility of a confrontation might arise; to wit, those who want to board as early as possible so as not to have to "deal with" the potential scenario of someone sitting in their assigned seat. By reducing the opportunities for confrontation (and therefore behavior correction), they are doing all of us a disservice. Neutrality is a myth. As Kierkegaard said, "you are choosing not to choose."