The banks will NOT reimburse you if their own ATMs spit out bogus (fake) yuan (rmb) bills. Has happened to several of my friends and the banks will not refund the money or issue legit money bills. Here's a typical scenario:
At first they'll say the hotel is responsible (the ATM is inside the Hyatt's lobby). The hotel manager says it's the bank's responsibility. So you end up going to the nearest branch and ask to speak to a supervisor. The manager persists that the money couldn't have come from their ATM. When you say there's video evidence (hotel lobby has several cameras) the tone changes and now he's implying that since you have counterfeit money on you then you're actually breaking the law! You're a criminal!
They'll make you leave the money and walk out of the bank! This despite having video proof of the ATM spitting out fake money.
Note, I'm not talking about some very well designed Chinese fake bills. No, rather discolored pieces of paper that happen to be the same size as their 100 yuan (~$15) bills. The size is the only thing that is correct. Wrong paper, wrong color, wrong everything, no text, you get the picture. if someone wants to go shopping they usually exchange $500 plus at a time (you can buy beautiful pearls in shanghai :)
Last time this happened a friend got over $600 in fake local currency. This is not that uncommon in red china, supposedly local cops are in on this "venture". So no ATMs in red china is my advice.
PS. The ultimate irony of it all is that if you have dollar or euro bills and try to exchange them for the local money at the hotel they will not accept ANY bills from you that have any tears in them, I mean it has to be almost perfect.