For the sake of the team-base pvp, party chat should be the only channel allowed, unless you don't mind loosing and being blamed, chewed up and spit out.
Good 'ol high-school, military antics,lol!

I would probably hate to be restricted and told what channels to have up during any event, it's up to the player is he/she can multitask. If you can't and voice-chat is the best option for players, why not toggle the chat window to vanish during PvP?

Nothing better than an invisible chat window(while it's idle) when sparks are flying.