I haven't seen it myself but this is in the September edition of Current Archaeology:
"Barrow saved from walkers.
Archaeologists had to climb 45 minutes there and back every day, to excavate a Bronze Age burial mound on the highest point in Carmarthenshire. It was being taken apart by walkers building a cairn around a 'geocache' box."
On a more jolly note there is an article about Seahenge and the carvings at Hunterheugh Crags, Northumberland.