In the book Customs and folklore of Worcestershire (Estragon 1970), the author, M Jones Lavender refers to a number of customs and superstitions. Under the general heading superstitions he relates,
"it is considered an ill omen or bad luck to carry a corpse across a field without the farmer's permission. This act also creates a right of way."
These two simple sentences imply several things. Firstly, why would you carry a corpse ACROSS a field and not use lanes or roads. It would seem that the observance of travelling in a straight line is being upheld here. The less respectful of us might also suggest that if you are carrying a corpse then that 'bad luck' has already happened! The idea that such an act 'creates a right of way' would seem to support the concept of the sanctity of these routes. You have literally 'ploughed a furrow' across the landscape.