In some airports, your technology will even be removed from your luggage by a helpful and diligent TSA or airline employee, and they will take it back to their own home for a very thorough functional check that may take years to complete.

http://blog.tsa.gov/2008/02/tsa-our-officers-public-and-thef...

CNN, Chicago Tribune, and ABC News ran a few stories about this "extra-special luggage screening" around 3-5 years ago, which I won't link because of autoplaying videos and/or slideshows.

In most modern western airports checked bags are scanned using a CT scanner rather than a 3 image x-ray that you see used for carry-on bags. This gives a much better image with more spatial clues regarding the contents and makes the resulting image much easier for automated detection assistance. Checked bags are also often passed by canine units for explosive detection.

I've read that too. The scanners for luggage are much better than those for the security lines. They might even use machine learning to detect things. I don't remember the source. sorry