To deal with the unexpected in Saul's system you just need an option called 'Unexpected.' Actually it's usually called 'contingency'. Some unexpected things might fall under, for example policing (an unforeseen riot or an unusually high number of prison break-outs).

And now that I've said that, I'm trying to imagine what is truly unexpected. Hurricane or tornado? Naw, they happen every year. Nuclear accident? Naw, at least yearly on average, or maybe only every decade, depending how it's defined. I guess it would have to mean stuff like epidemics or terrorist felling of buildings or poisoning of water supply--we gotta figure some domestic or imported jackass will succeed sooner or later but no one can predict when, where, or how extensive the event or its aftermath.

I wonder who should get to pick the wording used for each budget category and its explanation? That's where some of the budgeting power would lie, in creating what sounds like something people want to throw money at. So then what should the rules be, if any, for lobby groups in relation to this new budget system? Without advertising limits, such a system would quickly become corrupted as interest groups fund ads designed to attract tax money.

Anyway I definitely think it's worth a pilot project somewhere, if only to see what happens. I would love to know how human nature would average out in this situation; how similar or different would the priorities be compared what they are now?