Originally Posted by
FirstInFlight
You won't win this one on the merits - meaning that you were right and he should have been allowed to board. I would try booking another trip using the same search engine and taking screen shots. If there is no warning at all - the OTA may help you (technically still your responsibility but since the industry trend is to draw attantion to that issue...). You might discover that there us a warning that was perhaps overlooked.
This is very poor advice in all respects. Neither the airlines nor TAs (online and brick-mortar) can be expected to have all the updated visa requirements for all nations and all nationalities. As another poster has mentioned, there are other countries in the world other than the U.S. and Canada. TIMATIC is a very useful source of information, and a warning from the airline or TA at the time of booking might also be appreciated, but neither of them absolves the pax's ultimate responsibility to have the right paperwork prior to their international travel. If one finds China's TWOV rules to be bit arcane (which they are), the proper outlet for complaint is with the Chinese government. However, this doesn't mean that it will respond, let alone read it.