I was told its a capacity issue and that access would be for pax flying Qantas (i presume F and their emeralds) and flying F on BA (and I presume on Cathay and other OW who have F here, minus AS). Unclear if non AA OWE flying classes other than F, will have to inquire.
As a point of reference despite being BA Emerald i was always let in by virtue of an F transcon on AA, including tonight and almost on a weekly basis for the past few years. On non transcon AA itineraries they instead always check my FF status with BA, even if they know my face well and if its printed on the boarding pass.