Well, I call BS to they "never twitched!!!" I had to finish a doe off this season with my RSRH .44 mag with 240 gr. HP's! Without getting into gross details, lets just say she had nothing left between the ears! She kicked and twitched the whole time we were carrying her back to the 4 wheeler! (I know that was just nerves/muscle contractions, but the point is rarely does ANYTHING just drop!)
Besides this, seeing just ONE suffering animal in a lifetime is ENOUGH to discourage head/neck shots! Making a bad shot is one thing, making a dileberate "bad aim" is another!