Focus on Metal Detecting: Understanding What you are Digging up

UK metal detectorist James Warr attacks Paul Blinkhorn, because he made comments about some of the issues connected with artefact hunting on a Facebook thread (Paul Blinkhorn and his view on metal detectors. 2nd March 2014) on his TonyRobinsonsPants (sic) blog.  Mr Warr writes, referring to the PAS-inspired notion that artefact collectors are doing "work" for the nation, digging up its history: 

But still, yet again, we find more important things than you, [Mr Blinkhorn].  If we didn't find it, you couldn't comment on it.  Fact. I'll leave it there.  Paul [Blinkhorn] goes on a few other rants in that thread.  Mostly bitter, and jealous. I think level of knowledge of archaeology of the people involved is summed up by the quote from the idiot talking about spears being a sign of high status.

The metal detectorist's response to that is pretty telling. He says:

Unfortunately, not everyone has the time to fully educate themselves concerning spears. Some of us, are getting outside and saving history, rather than sitting on our backsides doing nothing, and testing our pointing finger.  This is a hobby.  Many people have jobs that aren't anything to do with history.

But then, if artefact hunting is not about educating oneself about the past, bang goes another of the PAS 'justifications' for encouraging it (PAStexporers). It seems to me that before anyone takes a spade to an archaeological site, they should make a little bit of an effort to prepare themselves cognitively for the operation. There has been enough destruction caused to the archaeological record by ignorant hoiking with no proper observation and understanding of the fragile traces surrounding the objects in situ. One cannot observe what one does not understand, nor can one even see what is to be observed without finding out first what kind of observations are needed in the interpretation of subtle and fragile archaeological evidence. Merely taking a spade to a feature and picking out what does not fall apart is hardly anything that is of any iuse to archaeology, even ersatz archaeology. Here again, the capacity of metal detectorists for learning is of vital importance to the actual contribution they can make to knowledge.