Yes, in many locations it is highly suggested to ask permission before entering certain forests and sacred land. I saw some tour bus that broke down and the tourists were all stuck. I heard a crystal clear voice say, that there were certain people in the group that did not respect the druids altar (stone circle in south Ireland) that they just visited. There are many stories of when some of the tourists do not respect the land, the fairies will defend themselves and play tricks on the people. For me, I had great experience there are felt very welcome. =)