i assume that's why at any sort of clays competition they have spotters to do nothing but keep their eyes on the target and watch for any indication of strikes.
At any major sporting clay event the trapper has the final say on whether a shot gets marked as an "X" or as a "0". The other members of the squad are also watching for breaks. However, just an indication of a hit is not justification for an "X", or "dead bird". The NSCA regulations say that there must be a visible chip, however small. Dust doesn't count, nor does the bird showing an obvious change in direction from being struck. There must be a visible chip. When I'm shooting I do not second guess the scorer, or members of my squad. Many times I have had a bird scored dead that several others saw a tiny chip come off of, but I didn't.
Yesterday while shooting in a registered event I saw a squad member's shot take the center out of the clay, without the rest of it breaking! Over untold thousands of targets I've seen shot at I've never seen that. The target had the face toward us and we all saw a big black hole appear in the orange target at the shot. Chips went out the back and were visible, but only if you were watching very closely.
Stan