[vmacosta]

In my experience, saying "you win" but not instantly mucking is always a weakish hand that doesn't want to show first, but has some small chance to win. It never really means I concede the pot and usually the angle is only to get info in an obnoxious fashion. FWIW, I'm pretty sure almost anyone except the very newest of comers knows this. I don't think it needs to be a rule because it will do more harm than good.

It is often a prick move though designed to obtain information without necessarily having to give t away.

I've done it several times but always stated my hand immediately afterward as PJ did (and I now regret each and every time).