I think the assumption is that there are articles so bad that it should be obvious that they are off-topic. In the past, I've submitted things on the border. I imagine many others have too. I've always counted on the groupthink to correct any errors in submission I might make. This seems to assume that there are hard guidelines. Watching the board over the years, I'm not sure that assumption is accurate.
Put differently, if you had a cache of really bad articles, shouldn't we see them? That way we'd know not to submit. But if you already know they're bad, then what's the point of voting or flagging?
Perhaps I'm just mentally adrift here. Honeypots make sense to me when we are talking about boolean things: a website visitor is either harmful or not. An email sender is either a spammer or not. But I'm not sure at all that this concept applies to something like an essay. Seems like if it would, you could just use the flagging behavior mentioned to rank the articles and dump everybody else's votes. Right? This is like verifying the voting behavior by setting up some completely different system to rank quality detectors. But if you could rank quality detectors, why keep the old system? And if not, how would you separate which parts of which system are useful and which are not?