Hi, GPS using b laowais in China is critical. I wanted to buy a camera with GPS, in China it was not possible, only in HK. In January 2017 I was arriving in Shanghai PVG Airport. There I was forced to go to costums clearance. They found my eTrex 10, explore it and confiscated it.
A friend of my lost his eTrex in Shanghai during a normal testing of GPS funktion in the Nanjing Lu. He was taken by the police and was asking for. This "interview" took a full day, after they confisating the etrex and he lost his visa (working visa).
So be very carefull in China when u do caching.