From what I read, the way mobile data roaming is designed is basically like a VPN that connects you to your own home provider. Thus if you're roaming in China y

From what I read, the way mobile data roaming is designed is basically like a VPN that connects you to your own home provider. Thus if you're roaming in China you don't get the renowned GFW hospitality. That's why some local people use foreign / HongKong sim cards for GFW-less mobile data.