The fundamental point I'd make is, no matter what reports such as these say, the damage isn't 'accidental'. It is vandalism, pure and simple. Picking up a stone or stones from an existing cairn and moving it somewhere else - even using the material to fashion another construction upon the cairn - is a conscious act. Not accidental. So what we are talking about is either:
1) Ignorance driving well meaning actions that nevertheless damage (in many cases) scheduled ancient monuments
2) Wilful damage to an ancient monument
Ignorance is no defence under law so both instances are, to my mind, crimes. However, clearly, it is impossible to police this except in fortuitous circumstances, so keeping tabs on your local area and reporting to the local authority, recording monuments for prosperity on TMA and other sites... basically raising awareness so 'ignorance' progressively becomes less of a defence... that seems the way forward for me.
In September we published an article by Heritage Trust member Roy Goutté and his TimeSeekers volunteer archaeological clearance group on the damage being done by visitors to the Neolithic site of Stowes Pound. Historic England, BBC News Cornwall and The Telegraph picked up on Roy and his team’s concerns and are urging visitors not to engage in the practice.
Full feature with links here.