Create a sneakernet. If you get a note, read it (don't talk to the person who handed it to you), then pass it on if you approve. In a city the density of Hong Kong, that's almost unstoppable.
Tech solutions won't work if they put you inside the Great Firewall, and force you to use MITMed HTTPS certs (blocking anything that looks like HTTPS). That last step is unlikely (since blocking or MITMing HTTPS would really hurt Hong Kong), but an alternative (a sneaker net) would be good to have, and render technical attacks less effective (so they might not even bother).
Tech solutions won't work if they put you inside the Great Firewall, and force you to use MITMed HTTPS certs (blocking anything that looks like HTTPS). That last step is unlikely (since blocking or MITMing HTTPS would really hurt Hong Kong), but an alternative (a sneaker net) would be good to have, and render technical attacks less effective (so they might not even bother).