I'm pretty sure it's always been allowed, at the very least as long as both teams agree.

Personally I think Islands are much more unbalanced and luck based than Caverns and makes me question my sanity to even play Islands, but they are the ones playing so as long as they have fun. 

Also, watching these as a spectator sucks not knowing what weapons the players have, imagine if you could be given a team colour as a spectator and cooperate with team whispers and see the weapons, would be a lot more fun.

cool to see some clan games played 

Hey! Welcome back Osito