At the exit from China they will ask on the basis of what document he can enter the UK and they will not let us leave with only his Chinese passport.
So remember, also take original and copy! Prostitution in Dongguan is illegal and thrives underground.
Someone at the front of the bus swipes all the cards and puts the notes in the cash slot, and then the cards are passed back and distributed to their owners.
Now, if the Chinese find out that you have an American passport, they will strip you of your Chinese hukou and possibly fine you.