Originally Posted by
BearX220
Those status readouts are not authoritative. They could fix the mechanical, make up time en route, swap aircraft, etc. -- all kinds of possibilities -- that put your flight back on schedule, and not send another update. If you slip your arrival time on the advice of the e-notifier, you risk missing your flight (happened to me on UA).
...and it would be your fault. Don't cut it too close.