My point was not that schools care explicitly what you wear but rather about your overall appearance. This could include clothing (though as i said not necessarily formal clothing), skin colour, height, build and general attractiveness (however you judge that).

I agree that training schools primary aim is to make money, they after all private businesses so it shouldn't come as any great surprise. The way they generally do this though is to sell an image rather than sell an educational experience. To sell that image they need foreign teachers who fit with the idea that a Chinese person has in their mind of what a foreign teacher is like.

Here's a hypothetical question

There are 2 schools that open next to each other that are exactly the same in all features with the exception of the foreign teaching staff

School 1 has 10 well dressed, tall, attractive, slim, white teachers all of which come from 1 of the big five countries

School 2 has 10 slightly tatty, plump, short, non-white teachers all of whom come from 1 of the big five countries

Which school will have more students after the 1st month of business?

When working for a private school i was explicitly told by the owner to find new teachers who were attractive, young and cool (i'd assume that for those who care, what you wear has some bearing on being 'cool'). I asked the owner if he'd like me to install a pink light in the reception area and we could pimp out these same sexy teachers after hours. It's unfortunate that sarcasm is wasted on most Chinese but it is good example of the style over content approach that most centres take towards recruitment.