IMHO, I believe it is common practice with Dangerous Game (DG), since in the case of wounded DG the PH gets to track it, "crawl in there" and clean up the mess any way so shooting while the animal is making his escape is only prudent. Part of the reason for this is so the wounded and enraged animal does not attack other unwary hunters on another day. I dare say a fair minority of the DG in record books in Africa was taken this way. The stakes are simply too high to screw around with the "he's mine, all mine" syndrome --- we're not in Kansas any more Todo.

Does it "taint" the record book, for the purists yes, for the pragmatics, no.

EKM