so... I couldn't find rules forbidding this. this is annoying during the harpoon wars and headshot wars. Is this forbidden? If this is not forbidden, i think there should be a rule forbidding this.
IMO it's not forbidden because they will start killing each other if they are the remaining players alive.
There is no rule forbidding teaming up in fun rounds. And making a rule about it wont speed up fun rounds anyways. As long as those players dont delay at the end then there is no reason to forbid friends from forming a spoken alliance during a fun round. Its called a fun round for more reasons than just a break from TTT, you should be allowed to play it how you want as long as you are not breaking the rules set for that specific fun round.
This is my favorite thing to do in fun rounds. It usually backfires on me though as people love to stab me in the back.
I can speak for a lot of the players here by saying this really isn't an issue as most of the time especially in harpoon wars/headshot wars, people who team up will usually kill each other in crossfire. Even then, as long as there is no delaying occurring, I wouldn't consider it an issue. It's just about having fun.
It is not a problem but RDM can occur in fun rounds. Specifically, team death match. Push your teammate off the building yeah we going have to do about it. Other fun rounds is pretty much free for all as every person for themselves. Having to teamed up to achieve the goal is one way and being alone is not always the only option.