Alright, let me explain myself. I was pondering tonight, as I often do, and I pondered something never pondered before. So, say you have a fief in strat. You set the tax rate to 15 percent, cool. However, you also have an option to set the tax rate to 10 percent for an allied faction; any member of that faction on strat would pay the corresponding tax. Maybe have it done per fief instead of faction-wide, meaning you could set clusterfuck castle to give remnant members a 15 percent tax, while fuckshitstack city gives them a 10 percent tax, ye dig?
Figure it'd be awesome for trade deals, diplomacy, etc. Not too hard to code, I imagine.