Well my experiences are with the Pebblebee tags but as my previous posts attests, they worked okay in OZ. And they seemed to work in China but I will have to add some caveats. I had an eSIM in my Pixel so all Internet was routed via HK so was not affected by the China firewall. I checked the tags when the suitcase with the tag inside was in my hotel room and it reported its location accurately. But I suspect it was just connected to my phone which was connected to the Google network so it reported correctly. It never occurred to me to check when I was on the road - I suspect it might not have worked but reported the last known location.