No, I'm recovering from a TBI and didn't take the time to consider my word choice carefully enough in my question.

I meant what the fuck is a catastrophic failure of a barcode reader and/or what the fuck barcode are you reading that contains information that's relevant to the safety?

The standards are all about probabilities of "catastrophic failure" and "failure on demand"

Is applying a SIL3 rating to a barcode reader just saying it's reliable at reading? Who certified it? What tests did they do? Without that info I wouldn't be able to figure out what the fuck they think it's safe for.

I've only ever used a performance level rating to assign risk for actual energy storage devices or hazard zones. Assigning a PL rating to a camera is like slapping an "asbestos free" label on the side of a cereal box.