Does anyone really do this to their cooling system?

I’ve been turning cars upside down to drain coolant since my father taught me years ago.

Well, your daddy do e taught you wrong. Everybody knows that you need to disconnect the radiator hose, get a friend d with a truck and a winch and drive it down to a quarry. You hook your bumper to the winch hook and lower it into the quarry. As you lower it, the old water drains s out. You then let the front end dip into the half filled quarry water a few times to wash the block out, and call it good. As an added bonus, the front end of the car gets washed too.