Just today a friend who sold their house couple weeks ago told me this: they had an internet-connected Wi-Fi lawn irrigation system. After selling their house, they had their internet service cancelled. Along with it the Wi-Fi system turned off of course. The irrigation system loosing the internet connection decided to turn on the irrigation with nobody able to turn it off as the new owners had not moved in yet. The lawn promptly flooded with water flowing to the street for two days straight. A worried neighbor called and the buyer's agent had to go to the house to manually turn off all water in the house. So much for smart IoT systems...