As for the S/O purportedly stood down for operating on the day, I call BS on that
As I understand it, the S/O in question was paxing to Perth (possibly Alt Paxing), missed his flight but arranged to pax on another carrier that was arriving in Perth just prior to the PER-LHR departure time. He did make it to the aircraft in time but had some other less-than-ideal 'notoriety' at the time which, combined with his paxing efforts, led to some Company sanctions.
At the end of the day, if you're Perth based then you are required to be available in Perth under the terms of the EA with regard to standby's and other duties. At the moment, how you get to the airport at the required time and fit for duty is up to you if you choose to commute from elsewhere.
If you negotiate to do a standby from Sydney or similar; good for you. I commute from Brisbane to Melbourne and have managed to negotiate quite a few standbys in Brissy, but that's usually been when there's the potential for me to be more useful to them in Brissy than Melbourne - eg: US to SYD/MEL flights diverting to Bris.