3 sounds reasonable. Maybe even 2. But it's a vote so if majority want the event that's why they vote yes.
about 3/5th of the entire server needs to vote in order to force a random event and vote kick/ban. maybe 2/5th doesn't want an event every single round (i personally wouldn't want one either. we had an event only server but that one quickly died out [even before we decided to close it]) the pop-up is annoying as well. i don't want to have to see that everytime after a vote has passed and/or failed.
The only problems I can see happening is Players forcing an event when the gamemode choose an event. Therefore overriding that event Multiple players forcing an event and overriding each others. IMO not much room for abuse so long as it is limited
If you read my last post, if there's a random event coming in the next round or an event already forced, dont allow tue command to work. Yeah I don't know how it could be abused.