I do not have any direct experience yet (new to bowhunting), but it makes sense. The way internal organs are innervated, you basically feel pain when they are stretched or there's an ischemic problem. I remember when spaying female dogs, in the rare case the anesthesia was not deep enough, we would notice not when using the scalpel, but when pulling out the womb (before cutting it free), which would cause a stretch of the organ and ligaments.
As someone else said, you need a sharp broadhead and not to touch the ribs. And I would think that if the animal is busy after females, or sees its herd around not being spooked, is probably going to make it think there's no danger. Just my two cents.
Max