Are sim cards easily swapped?
Very easily. Apple even specifically introduced dual-sim iPhone for China.
> How easily can a burner be used?
You need to bring your ID to a telecom to get a phone number legally. But I don't know if there is a black market for burner sims.
(Last time I've been there was a few years ago so take it with a grain of salt.)
Because they don't support eSIMs there.
Anyone from behind the great wall care to comment? Is HN event reachable from behind the great wall with out Tor?