In very dense fog on a country road near Reestdal your rear fog light is on. In the mirror you see that the car behind you has already slowed down a lot and keeps a wide distance; it has clearly seen you. What do you do with the rear fog light?
I leave it on, otherwise he will soon drive closer behind me again
I switch it off, because he has seen me and the bright light bothers him
I leave it on until the fog has completely lifted, even though he sees me
Explanation
False — You keep the light on until the fog is gone. Use the rear fog light only as long as it serves safety; if the driver behind has already seen you, the bright light actually bothers him (Book p.191).