In principle I'd agree that all the situations you've described are real and that you could find examples of them at many training schools. Of course it shouldn't come as any surprise that these schools are in it for the money, although it is a constant concern that they feel the best way to raise profits is to walk all over the teachers.

However, whether working for one of these schools means you will lose your soul or have to sell it I find difficult to believe and it sounds slightly melodramatic. You always have a choice and even where you've perhaps made a bad choice and find yourself in a difficult situation I don't believe that these employers can take anything more than time and material things from you.

However, if you're genuinely worried, Here would be my advice

1. Just don't work for them in the first place
2. Having taken a job, If conditions don't meet your expectations, leave
3. If you find yourself being fired for not meeting your employers expectations should you be that surprised (I've written about these jobs being very much like sales & marketing positions before. If you put up the numbers you're fine, if not ......)