Buying a SIM card for China abroad?

A group of German tourists who are going to China are looking for options to have a SIM card with a data plan while staying there.

Their own experience from previous trips, as well as some posts here (e.g. this one, or this one) indicate it can be difficult to get one without a Chinese ID card. As they will be travelling in a group, they cannot spend much time roaming the respective cities of their stay on their own to find "main offices".

There seem to be some options for SIM cards that can be ordered before the trip, while still in Europe, such as this one, or this one. These providers advertise quite large data packets (in the GB range).

Are such offers reliable?

I am wondering because they also advertise the absence of Chinese internet censorship, which cannot be something the Chinese government likes a lot. Thus, I'm afraid buying such a card might leave the tourists without service during the trip, as the Chinese authorities might "pull the plug" for such a service provider at any moment.