Originally Posted by
tauphi
This is not true. Plenty of PRC passport holders residing overseas do not hold hukou on the mainland. It is true however that most recent emigrants from mainland China have kept their hukou registration.
I have many Chinese friends in the US who have been in the US for 50-60 years who are still Chinese nationals (they chose not to naturalize to US citizenship) who have only recently returned to China after so many years still have their hukou and even got their national ID card renewed. They did "lose" their hukou book, but it was just a matter of getting it replaced.
Such a case as you describe exist just that I have not experience it with anyone I know. I can only offer my experience, perhaps you are right. I am wondering if the the OP's SO can see if she can get a hukou book replaced and get a replacement national ID; the recent real-name authentication for just about everything, having a Chinese ID is so much more convenient. There is a lot of scrutiny when you present a foreign passport or don't have your ID card when you're Chinese in China.