I tend to use hazard lights when reversing, as they are more visible. And if there is any risk of cars, people or lamp posts getting in my way then Mrs P stands at the back to (a) warn others and (b) tell me if there's a problem.
Personally, I don't think caravans should reverse on the highway without someone standing at the back. I know loads of people (esp those with a camera at the back of the van) will disagree, and I would be one of the first to say that I am a competent reverser. Trouble is, that is one huge blind spot - and it is difficult to judge distance when the back of the caravan is 10 metres away from you.
I would never say that some people shouldn't reverse at all, as it is fun to watch them on sites.