Originally Posted by
moondog
I still fail to compute any of the luck/risk at stake, assuming the actor isn't stupid enough to produce both documents at the same time. In other words, the exit guy isn't empowered to perform any crazy searches; show him the Chinese passport and move on.
The more I've thought about the OP's friend's case (during the evolution of this thread), the more I've come around to the idea that the original plan is/was solid.
OP wants to enter mainland China with PRC passport and leave with EU passport. The risk is that exit control will check his entry stamp on the EU passport. No entry stamp no exit.
If the OP uses his PRC passport to exit, he needs a valid visa. (Yes there are a few countries mainland Chinese can go without visa, but somehow the exit control guys don't seem to care)
I'm not familiar with the rules governing HK/TW id. I assume it's much easier as you basically have dual citizenship with two entities other than PRC.