Would it be possible to create a policy that accomplishes the same thing but doesn't use the vague concept of "spoiler" as the basis? (or at all) The current definition (as per
paragraph 1) seems like nothing more then a excuse to apply arbitrary judgment "on things you don't like", not a actual definition of the problem. Irenicus's post above is a good example how manipulative the policy is. Why is it wrong if someone sais: "Person A will be important." to be exact? given the stereotypes in anime I would say its a fair statement; there's no visible indication (s)he is basing the statement on some source of information either.
Also, in all this talk about the policy the supporters always bring up "intentional gray areas" and how you have to be "enlightened" to understand the so called "subtilitites" and such. Things like this should be taboo for a policy, are you telling us its intentionally written badly and that's good? Why bother writing rules down in that case? This is not some religious movement (I hope).