Not saying OP's info is bogus.

But want to add some info:

China has a very special billing system for mobile phone service. The phone fee increase *a lot* in a different province or area (a province is like a state). If people work and live in multiple area, it's very common to have two or more SIM cards to save money.

I used to work on phone business. The dual-SIM feature started in China first in around 2007 (IIRC) because people need 2 or more SIMs in a phone. Now even iPhone and Samsung have dual-SIM features in oversea models to satisfy the need in China (and maybe India).

So if people are forbidden to travel, they will stop their second mobile service.

I don't live in China, so some Chinese GLPers may chime in.