Read Thread: Revealing finders of mystery boxes
This may be a local thing but when I find a mystery box, I talk with the planter afterwards, and they often mention other finders. If you really want to know, ask the box owner.
If you've found the box, check the logbook within it? :-) That's really the only way to know since many don't record finds.
... Absolutely, when possible. But like I said in my original post, the original logbook was gone. The previous finders had kindly replaced it, I think because it was mush.