Hmm... interesting. So it depends on the sheath and the weapon? (Well, 'duh', sometimes I can be so thick )I'm too lazy to go back through the thread and quote the post, but I just wanted to say it's totally possible for a dagger or short-sword to ping when you remove it from a leather sheath. You have to draw it at an angle so the tip of the blade catches on the edge of the sheath. It makes that pinging sound when it comes free. The swishing is also optional, depending on how tight the sheath is and how fast you draw it. I have several daggers and swords (all functional) and was just experimenting. If I want to ping and swish for dramatic effect, it's pretty easy, though it can also be avoided.
I do wish some heroes avoided it though. When they're stalking, their swords start pinging and swishing, and that's just funny.
I can't dispute what you've experimented and the results you've gotten, but I think in my works I'll still go by what my sources have explained, especially 'cause I'll be using the types of swords and sheaths they use.
It depends a lot on the reader too what they find 'wrong.' I'm not terribly open-minded (o rly?), so I can get unusually nitpicky. Please, authors, don't think of readers like me when you're writing