Airline does not know how to handle in advance request for visa-free transit

I am traveling US - Japan - Shanghai - US. I know I qualify for the 72 hour free transit. According to the procedure listed here, I need to put my request for transit to the airline in advance so the aireline can declare this to the immigration Inspection prior to my arrival. However, when I called the airline to put in my request, nobody was aware of this policy and procedure. If they do not know how to do it, when I go to the free Transit Service counter in Shanghai, will they deny my request for free transit?