The case in the article matches the second model, not the first. Hundreds of people realised they were in a library with no staff. Two-hundred books were taken out, presumably without anyone having to log their names. That would have made it extremely easy for them to just keep the books. But they were returned.
Having few opportunistic thieves is, one would think, a good sign of societal trust and well-being.
I'll just mention that security at UK university libraries is fairly tight, I know people who have accidently taken out books without logging them, and just kept them, and there have been cases at Cambridge where quite high-value books have gone missing.