You know, I don't agree.
If a guy doesn't notice a screw missing, why should he notice a crack? A screw is VERY obvious to someone paying even marginal attention...
This is nothing but a failure of the dude at the very end of the line to even look (which really means a failure of the production management). My guess - they have a guy, they pay a guy and sometimes that guy just doesn't do his job. This happens EVERYWHERE stuff is manufactured; The difference is in the priority that the company puts in QA. If they were serious, they'd have a more senior guy doing it or a more rigid quality system.
Oh, and that finish crack (above pic) on a brand new bass would tick me off. Call them for a re-do.