Advice for those foreigners with Chinese spouses intent on teaching in China and unable to obtain Z visas.

1 - Don't accept posts in the area under the jurisdiction of the PSB that have issued your Residence Permit.
2 - Don't accept posts that require you to stay outside the workplace campus.
3 - Use a false name when you teach and speak to other people.
4 - Insist on being paid by your employer in cash, not via a bank.

Your chances of being found out will be virtually zero provided you maintain a low profile wherever you go and avoid telling other foreigners and any Chinese people you come into contact with that you are teaching without a Z visa.