dealer said it was to relieve pressure since its a small cabin you wont have to slam the door to close, so i would hope its an option to turn off or on somehow?
in fact theres no need to debate it, its on scions website as a feature: "simple shut windows" "Improves ease of closing door by allowing air to be released from the vehicle interior"
http://www.scion.com/cars/FR-S/features/#
so silly if you cant choose to disable it though...