On Thu, 17 Dec 2009 11:26:33 +0000, Peter Beale wrote:

I'm led to believe that that sort of thing also goes on in the event
of a plane crash (where the wreckage is recognisable as such).

Yup. Pretty much standard practice.

But why? What's the point of it? It seems just as stupid as blurring
out registration plates on cars in TV reports - anyone on the scene
could see them anyway.

Because most people seeing it on TV aren't ever going to see it at the
scene.