I thought it might be a good pass time to take up when walking the dog
But there seems to be much controversy about the topic
http://www.bbc.co.uk/iplayer/episode/b00nvz7l/Inside_Out_South_09_11_2009/
Whether you think metal detecting is a good thing or not, the last part of this report shows everything that is wrong with it (although slightly sensationalist).
The detectorists are metal detecting on a scheduled ancient monument which is illegal.
They are in a field without the landowners permission.
It is in the middle of the night.
When confronted they make a joke of the whole thing with agressive undertones.
They show physical agression towards the film crew
And lastly it can be deduced from these factors that anything they do find will certainly not be reported.
The detectorists in this report are nothing but theives.