I don't carry a neck knife, but am considering it. When out in the bush I often pick up something up and take it back to camp to process. So when I'm sitting down, suddenly my pocket or belt is not very accessible; but a neck knife would still be easy to reach.

With kids in camp I don't like leaving a knife lying around, I like it either in a hand being used, or safely in a sheath; once again if I'm sitting a neck knife would give good access and there is no chance of leaving it behind or losing it. I would always know where it was.