Peter wrote "It might also be a good idea to recognise in any policy the possible consequences of what might be considered innocent actions".
I learnt the hard way! Way back in Feburary, 1952 the north Derbyshire village of Winster experienced some very heavy earth tremors. The houses are all solidly built of stone and have stood for a few hundred years, cracks were caused in buildings, chimney stacks toppled etc. etc. The villagers knowing that large pipe worked lead mines containing large caverns lay beneath the village and wondered if they were collapsing and causing the tremors. My caving club volunteered to descend some of the shafts to find out but before we explored we walked the area with many of the villagers who knew a lot about the mines and minerals. One elderly spar miner who was also a Primative Methodist Preacher in his spare time, was particularly knowledgeable, not just of the Winster area but also of the Alport/Youlgreave area having with his brother worked down Mawstone mine, Youlgreave before the fatal accident at the mine in May, 1932 which killed five miners underground and three rescuers who perished attempting a rescue. He told us of the site of a small quarry where an unusual form of baryte called locally "oakstone" or "onyx stone" could be found. We left the quarry alone, never took anything from it or told anyone about it. However a few years later in the early 1960's I was at Magpie Cottage with a fellow member of PDMHS and the conversation got around to discussing this particular form of barytes and stupidly I gave him directions for finding the quarry where the small deposit was. This person, a geologist publishs lots of articles and books and he wrote about this deposit of "oakstone" giving it's location, in one of his publications. Yes, you can guess. Some idiot read about it, took a digger and excavated what was left of the "oakstone" leaving nothing whatsoever behind. Since then, unfortunately I do not disclose the location of any mine or quarry where I think mineral specimans can be stolen or damage done. A sad case of learning the hard way. As the main contributor for the lead mining section in the Bonsall Book (published in 2006) I had to be very careful in writing of the history of the Bonsall mines not to give the exact location of the mines I named, so that idiots could not go tramping over farmer's fields causing damage and trespassing. It's a sad world.