I got a reminder today to check itinerary change emails carefully. An upcoming itinerary had one flight rebooked to an earlier flight. So what you say? This flight not only departed before my connecting flight arrived, but it left around the same time the previous flight leaves. A totally impossible connection. To make matters worse, the email wording didn't mention the rebooking at all.
PLEASE NOTE CHANGE OF FLIGHT NUMBERS..FLIGHT TIMES HAVE REMAINED THE SAME
Oops. Fortunately this was all on one ticket and a simple search of the airline schedule provided me with an alternate flight (the last of the day) to suggest rebooking to (and a backup new routing if that failed). Easily fixed but I could have been stranded had I not read the email carefully.