When I'm scanning through text to see how something escalated I am constantly stopping to check if an inflamatory comment was visible to the reported summoner (ie. if they were being antagonised). I've not found private text between the enemy team helpful yet, so I wonder if it needs to be included in the tribunal.

For me it has been helpfull to identify a feeder, and it clears ou if the guy at the spot light is Assisting the enemy team, or simply having a real verbal fight or if hes just messing around.

You know dirty talking is not the same as insulting, but can be easily mistaken for one an other.

It is in some cases. Sometimes you can call locations and teamfights based on the chat, and sometimes you get indicators of some one feeding or afking.

Of course; reports are about players angered about having their match ruined. Surely (although not necessarily), they'll mention something.

I wonder about it too . . .

It's helpful in some cases and it's necessary in case the issue is over an inter-team obscenity contest. However, it would be nice if there was a way to toggle it on and off.