Everybody that speaks, writes, sings, etc to you directly or as part of a group would be physically incapable of saying something they knew to be untrue. Anybody attempting to lie would uncontrollably tell the truth instead. This only applies if you are physically in the audience. Example, btoadcasts and pre-recordings would not be covered by this, but all live performances would.

Or

You have a device, about the size of a mobile phone, that allows you to see and hear any event that has occurred. You only need to provide coordinates and a date to observe what happened at that place and time. Only events that are occurred 10 years or more ago and occurred on the planet Earth (up to 5 mi / 8 km above the surface) are accessible. You can swivel your perspective, but you cannot move around (so no following if your subject leaves the area or moving to peak behind / under anything). Once you start viewing a moment, events play out in real time and you can watch as long as you want. Nobody but you is able to witness the events and you cannot make any recordings.