I forget where I saw this (think it may have actually been a video), but they said the latest versions could work with the lights off as it is still flickering

I forget where I saw this (think it may have actually been a video), but they said the latest versions could work with the lights off as it is still flickering the light, but just dinner than what we could perceive. Of course this could with the assumption that the source I hard it from was correct and if so, then it's probably only feasible with lab grade sensors to pick up signals that sensitive.