This indeed a logical and well thought out answer. I work in a very small town in western Jiangsu and from what I was told, two other foriegners did runners at my present school because they did not like the place. I enjoy this little town because I like the peace and quiet. The apartment I am at is not so bad, the students are ok- not the best or wosrt I had-, and the teachers here are fairly honest and hard working people. It is thus up to a teacher to do their fair diligence to research a place and school before they come.
As to reasons to commit a runner, I would only recommend it if a person's life or health is in danger and no one at the contracting school would do anything about it. If it is solely because of any other inconvenience, just fininshing the contract for the year and moving on would be the best thing for the teacher to do. Maybe the teaher can negotiate an early release.
If the school does not live up to its contract comitment, a good riddance the next year is good- provided health and life are not in danger.