well?
i was trying to reverse out of a car park, as you do, i ended up letting the car behind me reverse first, kept looking, then again start to reverse, only for people to be walking directly behind the car! of course i stopped but they walked and the woman looked back at me, while walking, for ages, glaring.!
and no i dont have eyes in the back of my head, and yes i do have reverse lights!
if you take the risk of walking behind a car with its reverse lights on, you are taking a risk imo, and you dont turn and glare angrily at the reversing driver.