If you feel the need to eavesdrop on your friends, you must be concerned that they aren’t really your friends. You must be concerned that just maybe they have found a new group of friends.
There are still a number of secrets from World War 2 that haven’t been revealed. One is whether were were reading the British diplomatic and military traffic, and whether they were reading ours. I had the privilege of knowing a code breaker who worked in the Pacific theater, and asked whether we had been reading British mail. Instead of saying “I don’t know” or denying, he just refused to answer and changed the subject.
It happens.