I was just stating what the Shane advert implied, not that its contents were written in stone!
One would have thought that a long-established recruiter such as Shane ought to be aware of current Chinese visa regulations. But I'll grant you what Shane has placed in the ad could be a fabrication concocted to discourage non-native speakers from applying there.
That said, those who are displeased with my statement re it being a good thing if native speakers of English were only eligible for Z visas as foreign teachers of English owe it to me to click on: http://www.ycielts.com/main_guandian.php and then click on each of the four individual links, "Feeling of IELTS School". I think after having done so you'll have no choice but to agree with my statement because you'll have found it painfully easy to identify the two pieces that were composed by non-native speakers of English!