Jet II, you are conveniently forgetting that this company does like to enforce the bits of the contract that suit them i.e. the training bond.
Also the setup costs when first moving here is not inconsiderable. To walk away owing money at a time when there are few oportunities isn't a luxury many can afford in this environment.
The issue for these people, I believe, is that they left jobs to come here believing certain things that they were told through the recruitment process and now having left the job they had, find they are literally stuck.
It not as simple as "if you don't like it leave", that some like to trot out.