I've noticed that those who aren't actually qualified or experienced quickly learn that if they keep their heads down and just plod their way through their classes, they will likely be assured of job security.

Those from the Philippines or the African continent are especially careful to keep in the good books. They tend to agree to everything their employers ask them to do, and will bear contract violations without mentioning a word about them. Furthermore, they will sing their school's praises in order to make the headmaster happy. They wish to teach in China for as long as possible - they know that foreign teachers here have good jobs and plenty of money in their pockets.