The Idea is that sometimes the People living in the system have their own Idea of what would help them instead of us. Or to be more specific the fraction would.

So in general I thought of a system that counts hidden the amount of buildings and makes calc against it like: (Number of Factions in Senat [only If planetary main faction is one of it])*(number of buildings built by your choice)-(hapiness)-((number of allready voted buildings in this system)*3)-(Number of turn)/5)-100*[(number of turns when this event happend last[value cap at 10])/10]] = x


Its so far just a first shot calculation but I think it can transport the idea that its more like to happen when they´re not happy and/or the government is something like democratic and of course the building should not be able to be cancelled by  player and when destroyed it should generate a happiness reduction for x turns.


So when the trigger happens you willl be informed that there was a vote lead by a faction to built Building x (of course a factionspecific one but it could be one that brings no benefit in that system) So there can the player fell a descicion like let it happen (gives a hapiness boost for some turns/maybe the building itself will generate a hapiness boost for them as long as it stays?) falsify the vote to a building by your choice (cost something.... maybe influence and/or currency/ also had a chance to get  found out which should cause problems) or just ignore the vote (happiness will reduced for some turns).