I totally understand the need to respect the whole concept of a truly dead game dog my friend.
But I think we all have seen certain dogs who, though the may not have proven to be dead game, nonetheless are so far beyond the ordinary dog in their intensity that we feel something about them, that they really would be that game, if we took them that far.
I know I have felt that about certain dogs, that they were just way beyond the ordinary dog in their intense love of combat. So, though I never made the dog "prove" it was dead game, I just felt that they would be that game if I did so.
Jack