Originally Posted by
Doc Savage
Best bet is security cut the lock off to inspect the contents. Not sure why this seems so surprising to you, OP.
If you checked the contents of the bag, why would you then ask Customs to X-Ray it?
TSA approved lock with the TSA code on it. In PEK if security have to go through your case they will generally bring to the gate before boarding and go through it with you (seen this happen on a few occasions). There were only clothes and an empty rucksack in the case. Nothing to arouse suspicion on a X-ray machine.
As
skywardhunter commented, the concern was something being put in the bag. Maybe it's my job that brings these things to be watchful for.
S