sherlock, Its not a matter of seeing it from another side. In one case objects are collected, and information is lost. (Since I doubt that detectorists are going to be sifting through layers of soil, looking at plant, pollen, and carbon dating evidence with the rigour of scientific analysis) I dont know specifically what 'detectorists' are looking for, but knowing one metal detector enthusiast, he has no interest in anything except in finding some kind of salable collectible commodity (such as coins, jewellery) I dont see these people as any different from the Grave Robbers who pick out the gold jewellery from Moche Graves in south america. (I doubt they are interested in exploring local history). No doubt, as SRS mentioned above, archaeologists have been and are, guilty to some extent of imposing their own Eurocentric views and not treating other cultures burial sites with respect they deserve, although that's been changing.

A case in point, is the people who look through battle fields picking up bullets or shells. There was a recent article in an archaelogy magazine about an investigation into a 19th century Apache, US army battle in New MExico. The archaeology team collected, marked bullets and shells and measured trajectories etc. and was able to reconstruct a battle which historians had only some second hand information on. In essence they re-wrote history. All of that information would have been lost if someone went around collecting souvenirs on the battlefield.

Its as if someone had destroyed the rosetta stone in their haste to dig up gold treasures, we wouldnt know what all the squiggles meant.