Originally Posted by
MSPeconomist
Their trip must have been considered TRANSIT. There are now good possibilities for visa-free transit at major Chinese airports. The rules are different, for example, for PEK vs PVG. However, AFAIK just going to China and back, even for a short stay, does not qualify as one must be transiting to a third country. YMMV but I would never risk trying to get around the visa rules in this situation.
I took advantage of the visa-free transit in PVG last year to do a quick visit to see the expo. I flew NRT-PVG-ICN with 47:15 minutes on the ground in PVG. In the end it worked, but I had to convince the agent in NRT to issue my BP (she had to carefully read the exceptions), and I had to wait at immigration in PVG for about an hour while they verified my outbound flight (no idea why it took so long).