Good idea, SNM, my only problem is that if everyone has their own specific idea of what happened, then if you make a scenario that doesn't fit in with that idea, lots of people will be annoyed with your scenario to start with because it won't fit the 'facts', whereas if you start with a relatively neutral idea they may or may not like your setting, but it's more difficult to actually argue with its accuracy.
Although lots of people seem to like arguing about others' scenarios around here... maybe i'm just a chicken!
I guess the same kind of goes with putting a 'moral' in your story. If you pick a moral that isn't mainstream, for example a specific religious idea, then you must be prepared for backlash. So its up to you; are you doing this for other's entertainment, or to try and preach? Or are you just trying to put a moral in to make the story seem more real, as if it really matters what happens in the scenario?
I'm on the pc, so i haven't played any user scenarios for BoA yet, but I have read through the reviews of the two that are there. One of them got some scathing reviews because it was preachy. However, on the tables list it actually says a description something like 'when god declares war on the modern' (i think) so at least people were warned.
Hmm I don't really think I have an argument here, just a listing of ideas. If you have a well done moral to your story, it can add realism to it. If you have a preachy moral, it can bug people who are just here for entertainment. If you can handle the criticism, you can at least be happy that some might listen to your 'message'. But those who are annoyed may avoid any scenarios you make in the future.