Most of us already know that the seatmap is an unreliable indicator of how full a flight is. Oftentimes, the seatmap will show that a flight is full, or nearly full, although expertflyer will show lots of availability. This almost always is a function of (1) AA's practice of blocking seats for airport assignment, which causes the seatmap to show that certain seats are occupied even when they are not, and (2) AA's -- and many airlines' -- practice of overselling flights. Yet notwithstanding this, many on this board continue to use seatmaps as a proxy for availability.

Today I experienced something which I found to be a little unusual, but is yet further evidence that seatmaps cannot be relied upon. I booked myself on AA4618 JFK-BOS for one afternoon next week (I won't tell you which day: I don't need any of you jokesters -- brp -- to go and cancel my reservation!). Expertflyer showed the flight at Y2, which most know means that AA is willing to sell exactly two more seats on this flight, and probably means that the flight is (or will be once these last two seats are sold) oversold. The seatmap, however, showed 13 of the 37 seats as available. Someone relying on the seatmap might conclude that the flight is wide open and they would, of course, be completely wrong.