I am having a similar problem. My host is asking for $80 / person to register us. I called airbnb and they are not familiar with these registration rules. It seems the host is obliged to register you but there is no way to force them to do so and therefore you are open to extortion.
With the new decree it seems that instead of the 24 hr registration requirement, it extends it 72hrs.
Still not clear if you are not in one city longer than 72 hrs whether you still need to register.
Airbnb should have a clear stand on this to prevent their costumer to be open to extortion.