text: They probably don't exist at all.  If they do exist, they're likely to be on a different alignment.  
  
  Taking http://www.openstreetmap.org/way/36350769 as an example, it's "foot=unknown, highway=footway, source=npe".  "npe" means "New Popular Edition" (out-of-copyright OS maps from 50 years ago or more).
  
  Although I wouldn't have added them in the first place (things like this actually make proper surveying harder, not easier), and they don't really add anything to the map, I've not deleted them as they don't really "get in the way".  Obviously when things get surveyed properly on the ground they can get deleted or moved to where the real path is.  I certainly wouldn't join them to roads as in most cases they really don't exist.
  
  I've done quite a few bits and pieces around here but obviously haven't been past either end of this alleged path.