I don't think anyone has implied that sword knots were knot (
) universal, or confined to naval use. You landlubbers are just as likely to drop something as us naval types, more so if you are on a horse.
A ring can, thru wear or trauma, break off any time after it was out of serve and the sword knot crumbled to dust, thus leaving us with a hole that may have once been occupied. I do think most if not all swords in service would have had an appropriate sword knot during their active service life, whatever their service branch, as they do now. Even the helmet pommeled cross guard one.
Hotspur has a very cool collection by the way. Very nice swords all.