Had the range been clear and the RO been able to stop him quick enough, I'd have no problem giving the new shooter a break. With someone down range, no question about it, DQ.
I have seen plenty of questionable calls and felt it wasn't place to say anything. Had I been the guy down range, I would have no problem voicing my concerns. If the call were to stand, I would probably change squads or go home. The RO that did not DQ him probably would have felt differently if he had been the one downrange.