How dumb do you want the medical examiner?
Once the heart stops beating, blood flow ceases other than as a result of gravity. In a living body, blood will flow uphill and be forced out any cuts. In a dead body, you can get blood to flow out only through gravity, which is why hunters hang meat.
Any hunter or butcher can tell the difference.
Let's say a body is lying face up on the ground and dead. You slice across the stomach about an inch deep. If you then pull the skin open from the slice, you'll see very little if any blood. Normally, in a living human, this wound will bleed a lot.
Bruising after death shows up by observing the damaged cells. There is again little or no blood that will be in the bruised area.
Even if you cut in an area where there will be bleeding from the pooled blood because of gravity, the flow will be markedly different than in a living human. Blood in a living human is at a pressure of 2.32 psi/1.55 psi (120/80). Gravity flow will be at less than 1.00 psi. In a dead body, it's going to ooze more than flow because of this lack of pressure.
Whoever said that post-mortem pooled blood would mimic pre-mortem blood in flow is either making a very qualified statement or doesn't know anything about autopsies.
Best of luck,
Jim Clark-Dawe