When doing TWOV at PVG I've been asked to show written confirmations for hotel reservations and even questioned about the location of my hotel, the former StR in Pudong, where they didn't seem to recognize the street and were only satisfied that it was in Shanghai when I said that the hotel was pretty close to the Century whatever subway station.

I've advised people before to carry written printouts of hotel reservations when doing TWOV but others here have asserted that this is unnecessary.