[apetresc]

Why would a knife be a problem in a checked bag, even if it hadn't been sealed in the original package?

[fusslo]

I've asked TSA people similar questions when they checked my bag. He said that the item was blocking view of what was underneath it.

I'd guess it's not the packaging, but a big piece of steel blocking the xray view.

[gib444]

The x-ray machine aren't 360?

If 360, I wonder does the operator perhaps not trust it?

[kotaKat]

CT baggage inspection is (fairly) new and only used in some places like carry-on screening. This was probably a behind-the-scenes belt x-ray planar image where the giant chunk of metal blocked everything underneath, so they kicked the bag out for a quick look somewhere along the line.

It’s not too unsurprising to see bags routinely get re-xrayed in the belt system when they come off of flights back stage.

[fusslo]

probably different fidelity of scanner, I'd guess. This was in 2018-2019