From the Virginian Pilot comes this article: “Jails are all ears for inmates’ phone calls.”
The article is long, but well written. It explains the various ways that jail phone calls can, and often do, impact the outcome of a criminal case.
Every time I visit a client in jail, one of the first things I explain is that every phone call is being recorded. Every. Single. Call. And prosecutors regularly listen to the jail phone calls!
The same holds true for visitation and mail. All of the inmate visits are recorded. And all of the inmate mail is screened.
An inmate can only have a private conversation with one person: their attorney! Attorney phone calls and attorney visits are completely privileged and confidential.
For my clients, I explain that they can talk to their friends and family about how they are feeling. They can talk about how they want to be back home, how their day is going, or whether the family is doing well. All of that stuff is almost completely inconsequential.
Under no circumstances, however, can they talk about what happened that led to them being arrested. They cannot talk about what happened during or after their arrest. And they should not talk about the progression of their case, other than general information (e.g., court dates).
P.S. In addition to the warning about phone calls, I also explain to my clients that they should never talk to other inmates about their case. At all! The client must assume that every other inmate will attempt to “snitch” if they have the opportunity. And this will happen regardless of whether the information is true. Even where another inmate only has basic information about a charge, the “snitch” will fill in the missing details with untrue information and pass it to the Commonwealth. If they are believable, they might receive a benefit in their own case. If they are not believable, there are no consequences. In that regard, the "snitch" has nothing to lose!