What if you do not check-in to a hotel after entering China?

What happens if someone does not appear for check-in at the hotel after entering China. As I know they scan passports at hotels. Does it go to a central database where they can trace it that there was or was no check-in after arrival? If there is no check-in, can this person still travel for example by train? As I know they also need your passport for a train ticket. Is this system linked with the central database if any?