I interviewed my mother about 3 weeks before she passed away in 2017. Not only did I get some gems from her, I managed to capture my 3 yr old son spontaneously singing Twinkle Twinkle Little Star to her. I had no intention on telling her that I recorded her, and that's because ultimately it wasn't FOR her, and I knew she wouldn't be around very long and I wanted something more substantial to have other than short, meaningless voicemails saying "Call me back".