It's not about knowing the identity of the person, it's knowing how they are going to proceed in arguing their case. Setting up an argument takes a lot of time, it's their strategy for winning a case / defending their client. Knowing this beforehand will put one side at an advantage in preparing their case and specifically aim at any faults in arguments.
Also why is "win" in quotes? There's generally no winners in flame wars, but in a court of law decisions are made on who wins and loses unless there's a mistrial/deals being cut by both sides. So being able to concentrate efforts directly preparing against a known strategy that the opponent is using is a big advantage.
Because,
> There's generally no winners in flame wars
Is that a euphemism for "intimidate them into shutting up"?
So knowing strategies doesn't really help, because you kind of already know the strategy and have prepared your response.
Now - if you are guilty, and you tell your lawyer where you buried the bodies and the police happen to let a cadavar dog lose in that general location ...
However, I agree with the first poster - there should be an official secure channel for communicating with counsel after you are convicted.
This does release the Kafka-esque possibility of being indicted for contempt of court or obstruction of justice by telling a lie to your lawyer in a supposedly private email, and then the cops wasting lots of money on it.
If you can avoid indictment under the above, this is an interesting DDOS opportunity against the system. All prisoners should immediately email their lawyer that they know where Jimmy Hoffa is buried etc. Send three "private" emails to your lawyer with three different strategies and then conduct a fourth at trial. Something like that.