Don't they require a state-run app on everyone's phones as part of their social credit system? It should at least know who is using the mesh app if nothing else?
AFAIK, even in China you're not required to do such except perhaps being a Uyghur in Xinjiang...
However, the PRC government is believed to have full access to popular apps like WeChat, among other surveillance tools.
If I were to do it, maybe I'd just ask phone makers to install such tools as system or ring-0 apps. Why would I give the people a chance to choose whether to participate in my mass surveillance scheme?