As I used to work as a dispatcher for Troop I, private calls are really nothing to listen too. Usually its mainly used for desk to trooper talking without tying up the main or secondary troop channels. It is also utilized when there is a lot of information that needs to be given out to a trooper when he / she requests information from NCIC / COLLECT when it is extensive. Other than that it not really used for important information.
You'll hear more "Code B" on the main channels anyway.