I may be pro "rushing," but I am pro rushing when the teams are relatively balanced and it's a relatively even fight. To me, this is not rushing. To a lot of others; it is. While I will not take part in a 3 vs 1 onslaught, I do know it's going to happen and it's part of the game. Put in too many rules and guidelines and the game becomes boring and slow. I like PvP because it's fast and different from PvE.

And having a "ready" button only works before the match starts. If we're forced to wait for a game to fill up before playing, you're going to be sitting around for like 30 minutes waiting for PUG matches to start.
This what I am trying to explain to you but you never seem to actually listen. In THIS game rushing has been defined as attacking other players before rules have been set in place. Whether it be 1vs1 or FFA. Having an option when joining a PvP map that allows players to declare that they are ready would not slow anyone down. As long as everyone can communicate at all times via chat function.

Example -

Player 1,2 join a map on separate teams.

Players join opposite teams.

Players agree to 1vs1 until room fills. Both click " Ready " and begin to duel.

Player 3 joins.

Does not click ready. Asks what the deal is. Is told 1vs1 until room fills.

Player 3 clicks " Ready ".

This prevents players being taken advantage of. And in no way slows down game play. Or allow anyone to take advantage of others.

I suppose having a vote kick/boot options would help also. For those players who just don't listen.