An interesting little snippet from the British Footpaths Handbook:

There are no laws of trespass in Scotland. If you do no damage, you are free to go where you will. This seems a great advantage at first … there is a sort of utopian freedom to roam. But no official trespass laws means also no official "rights-of-way". Thus maps of Scotland do not have the friendly little red dashes indicating footpaths, which walkers in England have come to love and rely upon.