Example A: What if I were to record a friend of mine who complains about her husband and then the next day says she didn't say "any of that"? This would prove to her that she did say the things she did. Legal or illegal?
Example B: What if I were to record my boss yelling at us (me and my co-worker) in a very unprofessional manner? This would show our (even higher) boss that she acts all nice to us when he's around but is really the sister of the wicked witch of the west. Legal or illegal?