The government can and does eavesdrop on cell phone conversations, on a very regular basis. It is a fact that 'they' can listen to any conversations you are having in a room with your cell phone, even if it is turned off, even if you are not actually talking on the phone. The only way to assure that 'they' are not doing that, is to take the battery pack out of your cell phone. I have family in the military, and they know people who know people
. The fact of the matter is, they don't care about you or your wife or what you are doing. No offense but you are not that important to them. They hear some great stuff though....the people assigned to that job, love it!
OnStar is also rumored to be able to have this ability to listen in via remote.
There are programs that the SO can order and eavesdrop, as well. If your phone has GPS, it is compatible with this software, and it is fairly easy to purchase online. Your best bet, if that is your fear, is to buy a 'throwaway' or pre-paid phone, like a Tracfone or something similar, no-frills, just your basic phone with no extras like GPS.