Originally Posted by
Loren Pechtel
Second this. Checking in requires your passport and visa (if your visa is in an old passport you'll need to present them both).
Your brother had better be registered somewhere (or have a good reason he's not--for example, the night we spent on a long distance train.) There have been incidents of people being caught after the fact for not having registered, thus the system is capable of associating the registrations with the visitor. Don't take chances!
OP, I hope it is clear by now both you and your brother have to register with your passports. They are scanned and uploaded to the local police registration office. Two people can be in one room, that's no problem, but both have to register.
I cannot imagine if you have registered yourself in both rooms that would be a problem, the police are concerned if someone is NOT registered. Just make sure your brother is registered.