Speaking of your scenario, a few games ago, all of the "bad guys" had the most votes, and the good guys all left the UP
lol, similar thing happened in my current game. The altarians are the most powerful empire except for my own and because I am the head of the UP and at war with they defied my UP resolution and left. Even though the resolution was merely about giving everyone extra trade routes and even though I myself voted against it anyway...
Oh well, I guess it's nice that the only major UP nation besides me is gone so that I now have a total monopoly over it!
Can you provide any additional ideas for "Evil UP" resolution proposals?
Yes. Here are some suggestions:
1. Rename the United Planets into The Imperial Coalition.
Effect: United Planets is renamed into the Imperial Coalition, and evil empires get a 20% morale bonus for 25 turns.
2. Ban trade with good empires.
Effect: Nobody can trade with good empires.
3. Armament cooperation treaty.
Effect: All evil empires gain a 20% production bonus for their shipyards for 20 turns.
4. Holy war.
Effect: All evil factions go to war with the targeted faction.
5. Galactic oppression celebration day.
Effect: All evil empires get a 50% morale boost for 20 turns.
EDIT: And one more so that the UP can be changed again in case nr.1 happens:
6. Rename the Imperial Coalition into the United Planets.
Effect: The Imperial Coalition is renamed into the United Planets and good empires get a 20% morale bonus for 25 turns.
Just ideas... 
EDIT: Can these be modded in? It would be so awesome.