You are wrong about the Chinese "using" the Witnesses to learn English. My mum offers bible studies and tells them that if nothing else it will help their English. She's got loads of studies with students, is learning Chinese and has a ball with them. They cook for her, bring her small gifts and letters from their parents thanking her for taking an interest in their kids. They all treat her with tremendous respect. None of them are baptised and I don't think any of those that have returned to China have continued their study.
She's also in contact with Witnesses in Beijing. They are ther under the auspices of learning Chinese but are missionary sleeper cells. They email each other in a kind of code stripped of any religious/spiritual terminology in case it's read.
Here they have a Mandarin congregation and in Glasgow they have Mandarin and Cantonese congregations and she's been to Belfast for a circuit assembly and Birmingham for the district assembly.
It's all the rage.