I've never had this happen to me fortunately, but I was always surprised to see the number of corrections published in the magazines I used to subscribe to. It's understandable that mistakes occur once in a while, but they seem to crop up far too often. Just once I happened to notice a correction to a pattern I had intended to make but hadn't started yet. That time I was able to make a note of the changes, but what if I hadn't seen the correction or my subscription ran out and I never even got the correction?