I was listening to NPR recently and there was an interview with a former Clinton administration official [1] who mentioned almost in passing that prosecutors regularly infringe on the right to privileged conversation between a defendant and their lawyer. Specifically, he mentioned that the room you are given with your lawyer has paper thin walls that the police and prosecutor folks can hear through easily, and when in jail there is no way to have a real private conversation with your lawyer as well.
Think of it this way: you're in jail and you're talking to your lawyer about what he thinks the prosecutor's strategy will be, and how he's going to defend you against it. That has nothing to do with evidence admissibility but could still be damaging to your case if the prosecutor finds out about it.
I talked to a relative who is a lawyer and was told that court cases are not dramatic as seen on TV. Both the prosecutor and defense side have access to all documents and have ample time to prepare their arguments. There are no surprises in court (if there is either side can ask for more time to prepare based on new info).
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.
"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 ..."
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.
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.
[1] http://wfae.org/post/webb-hubbell