What happens now on new Ancestry projects is that each piece of paper is transcribed independently by two volunteer keyers. Their results are then sent to an arbitrator, who will decide which is right, if the transcriptions are different. If a keyer is found to be wrong, that knocks off a point from their accuracy rating. Keyers with high accuracy scores are invited to become arbitrators. So, if you see what you think you have seen a mistake in the latest Ancestry offerings, that mistake has been made by at least two people, if not three. And it does happen - I was looking at a new release of postcards on Ancestry recently, and I noticed one or two "howlers".