Okay I'll tackle a difficult subject.... They should'nt be there, and therefore can be removed. Apart from the fact that it's tacky, what on earth are people thinking that megalithic stone circles, barrows and standing stones need a superstitious relic from one religion placed on these sites.
Think if you read Julian Cope's TMA book Megadread, he seems to have always carried a plastic bag for removal of rubbish - if you prise the two pieces of wood apart they become just that two pieces of wood - symbolism destroyed...