It would have to have been programmed through Manager. A user cannot give themselves permission to listen to another caller. The user trying to listen would need permission to listen and the user being listened to would need settings set so they could be listened to. By default, the system is set against these settings. Also, by default the caller being listened to would hear a beep when the other user joined the call. Again, this setting can be taken away so ne beep is heard, but not by the user. Only by the admin. So, I doubt they are listening unless they have access to the admin software.