I'd have to say yes. Where most neck knives I have seen are carried upside down gravity is working on the knife to drop it from the sheath. On a belt gravity is actually helping keep it in its sheath. Yes I understand friction is keeping it in there, but over time with lots of sheathing and unsheathing at some point it will become looser. At what point you reach that stage is another matter, it could take years.Is a knife any more likely to come out of a safe, secure and correctly made sheath if it is hanging round your neck, than in your pocket or on your belt?
Have you ever tried it?
I'm neither advocating for or against, just pointing out that for 2 sheaths of the same quality it is more likely due to pesky physics.
