OK, you're right, what I did mean was "seeing" what actually happens, which I meant as a judgement call only in the sense of deciding whether you actually saw what you think you saw. But correct, that was NOT a judgement call, because the rule makes it clear. What I'm saying is that rule needs reviewing, to say that being DOWN includes being tackled by an opponent, losing balance and coming in contact with another player involved in the play also on the ground as a result of the play, yadda yadda yadda.
Consider a tackler meeting a ball carrier head on, tackling him, the runner falling directly on top of him on the ground, but getting up and continuing the play because the tackler was beneath him and prevented him from touching down with an elbow or knee. I'm sorry, but in my book, that player is DOWN.