I know a whole lot of people who don't know when to let go, so how can it be an "instinct"? Ducking when someone throws a punch is instinct. Throwing a ball is learned.
Also, I hear a lot about some guns that point "instinctively", as if their design makes hitting with them as easy as pointing your finger. The problem with that, is the two guns that I hear most often are great instinctive pointers - the Luger and the Peacemaker - are two of the WORST pointing guns I have ever handled.