Going through passports faster than the average is nothing compared to advantages such as avoiding medicals and visa runs to HK/UB.

Given the new costs for UK passports overseas, I hope that those words don't come back to bite you. Who knows as you are retired and wealthy, I presume, maybe the cash is not a concern, but at the ballache level alone, it is a nightmare. Why are you so concerned about avoiding medicals? Just curious? And HK isn't all that bad as a break from the mainland, a free press, internet without a vpn, good beer and food....owch! Nothing personal, just wondering why you are so staunchly steadfast on these issues?

As for release letters, they don't apply.

Why?

I reckon there are at least 30 foreigners teaching on behalf of the three Yuncheng agents on L or X or F visas.

Regardless of what you say, the authorities can still boot them out. It has happened before when they decide to do things on a whim...

The local PSB turn a blind eye. If they dare to take action against foreign teachers teaching illegally, they will be fired by the mayor.

The mayor is still Chinese right? Yeah, I know China is different from a western country, and the rural areas differ from Shanghai, but it's not like FT's are investors bringing in millions in hard currency. They have in the past, and can in the present, take action.

I guess the mayor and the PSB get regular bungs from the three local agents.

Quite possible, however, I still wouldn't chance it. I'd rather sleep at night, without sweating a knock on the door and a trip down to the psb....

Just me though...again, not personal.