If there is a private footpath, then I suggest tagging it as such, using the access=private tag. If the footpath follows a slightly different route than what is mapped I suggest updating the geometry. It it is not there at all I suggest deleting it.

You don't have to ask permission to fix something that is mapped incorrectly. And doing so yourself is much more efficient than leaving a note. Particularly when you have local knowledge (which it seems like you do).