I think you've just perfectly illustrated how some Scope Insensitivity can be good thing.

Because a mind with perfect scope sensitivity, will be diverted into chasing impossibly tiny probabilities for impossibly large rewards. If a good rationalist must win, then a good rationalist should commit to avoiding supposed rationality that makes him lose like that.

So, here's a solution. If a probability is too tiny to be reasonably likely to occur in your lifespan, treat its bait as actually impossible. If you don't, you'll inevitably crash into effective ineffectiveness.