Threats are things so bad we don't actually believe in them.
If we do believe they might really happen, they are worst cases.
The reason to do brainstorming to outline threats is the same as to outline visions: It establishes clearly the limits of what you do and don't believe in, making use case analysis more efficient and guiding the writing of new stories, while still letting you think "out of the box", construct stories and useful conceptual metaphor, etc.. It lets you list bad things without getting into a lot of rhetoric about it.
It also reveals what you are thinking about the extremes of good and bad, in case someone else reads it and says "hey wait a minute I *do* believe in that..." in which case they move it to best cases or worst cases. To do this in a disciplined way makes it really clear where our various ideas of reality converge and where they do not. Persistent differences in this might make it obvious where factions are.
Here are some threats:
0. Consumerium suppresses the New Troll point of view, raising neutral point of view to religion, empowering cliques, and generally making it impossible to challenge anything they say even if it is totally false. In other words, it degrades into Wikipedia. Even the same people run it, like the Mediawiki developers and Wikimedia founders, who have no values worth respecting.
1. Lawyers specializing in hot potato lawsuits only against the poorest members of the Consumerium Governance Organization, and only for doing things that they really need to do to make Consumerium governance work.
3. Gus Kouwenhoven taking over the CGO and steering it "his" way.
4. Consumerium:itself ignores comprehensive outcome of its advice. All forests disappear and all things on Earth die as a direct result of its use - for instance, in Haiti, the healthy organically grown rice and beans sold via the healthy buying infrastructure, which take more water and longer cooking to prepare, cause the forests disappear since more charcoal is used. Meanwhile, in Congo, ape extinction occurs and forests are totally destroyed as miners and loggers wipe out the forest to get tantallum to meet the hardware requirements. By ignoring the deepest outcomes of following its advice, Consumerium itself becomes the worst problem.