We looked at a house recently for sale by owner that we really liked. The owner showed a few things then stepped out so we could look at it privately. We didn't gush too much about it inside but pointed out a few things we liked and discussed if we should make an offer. A few days later when negotiating the owner was pointing out word for word the same things we mentioned we liked. When we walked through a second time we asked about the security system & that's when we learned it had interior cameras very discreet in the alarm's motion sensor. Contacted the alarm company & sure enough it records sound and video. I am certain they listened to our conversation. Too many things we said were repeated verbatim to be a coincidence. Ethical or not, it happens. I am sure some more unscrupulous types also put their phones somewhere to record & use it to their advantage.