Last time I was there, after handing my bags over I got called to the inspector's room. They'd x-rayed my bags and seen a cigarette lighter [1]. I have no idea how they recognized it as such, but they pointed to the area in my bag where it had been seen, and asked me to open the bag and remove it.
On another flight, we were all waiting in line to check-in, but the agents hadn't shown up. Somebody gave up on waiting, and just left their bags sitting in line - this while the recording about unattended bags was playing (yes, they've got that in China, too). It was funny to watch everyone in the line studiously ignoring the unattended bag, for fear that they'd shut down the terminal while calling the bomb squad, and we'd all miss our plane.
[1] I don't smoke, but it's in my first aid kit for sterilizing a needle.