You don’t have to add it to every path. Let’s say it was just D:\Client Data\Pat Pritchard.
If they somehow never moved their files from that path, all you would have to do is add in D:\Client Data\Pat Pritchard|Pat Pritchard/optional
Or, if it was constantly moved around in Client Data, then just make it D:\Client Data|Client Data/optional
I do agree that making every path optional is just horrible within itself, but just trying to give you options to make it work.
Alternatively, you could just smack the person hard enough until they stop moving their files around, or make them a static folder that they couldn’t move – tell him that only stuff in this folder is being backed up, and anything and everything that is not in that folder will not be backed up.
Whatever you stick with, I hope it goes well for you @hippy1970.