Just shoot (other than Customs and security areas), and if anyone in authority tries to hassle you, put the camera away and walk. The BAA link is intended for commercial/journo photogs; a blanket ban on photos by tourists would result in some ugly scenes in the waiting areas if security tried to wrestle cameras away from all the passengers shooting "This is us at the boarding gate" pictures for their scrapbook (or hard drive, or wherever people stores those things these days).