Facebook, Google and Wikipedia are banned in China, and many other sites. Accessing them as w means breaking the law. Since the censorship is mostly for political reasons, accessing those sites illegally would embroil you in a sensitive issue.
I guess for most foreigners, it would be very difficult from refraining to visit those sites
This is an amusing take. Nobody cares if you (as a foreign tourist) go to those sites, in fact if you’re on T-Mobile roaming or in a hotel that caters to westerners, you don’t go through the firewall at all.
I was surprised that you can buy sim cards in HK which are completely uncensored and use them in mainland china, using the same exact networks too (so no slow roaming speeds).
I guess for most foreigners, it would be very difficult from refraining to visit those sites