I'd also include under 'trivial' things like "Will this 6-sided die roll a 1?", or really any other well-understood i.i.d. process whose distribution of outcome

I'd also include under 'trivial' things like "Will this 6-sided die roll a 1?", or really any other well-understood i.i.d. process whose distribution of outcomes never changes under reasonable circumstances. Not just things that are 0.1% or 99.9%. > Who would be gaming the system here anyway, the site? Individual users? Cynically speaking, users would be incentivized to ask and answer more trivial questions to pad out their predictive accuracy, so they can advertise that accuracy elsewhere for social clout.