Take it from this point of view.
Lets say, you have lounge access, either QP or QFd J lounge access, either via the credit card you hold, or due to the fact you have QFF SG, in both MEL and SYD, the QP or QFd J lounge are in the other terminals, and they are not linked, so you have to trudge between terminals to access them.
My several JQ flights, 2 or 3 a long while back, were ok, till the time they cancelled my JQd flight, wihtout notification.
I was to fly MEL - ADL with JQ, 24 hours before flight, tried OLCI on the JQ website, cannot be done, they probably already knew that that particular evening flight, had been cancelled, but they didn't say so.
Tried to do check in at a kiosk at T4, nope, cannot be done, come back later.
So went to the QP at MEL T1, and it was in there, that I got the notification the JQ flight was cancelled, offered another flight the next day, but I had to start work early.
So rushed out of the lounge, packing up all my things, and went down to QF desk sales, and bought a flex Y tix.
In the rush to get back to the secure side of T1, 2nd entry that day, I accidentally left my mobile phone at the security screening point!
Got to lounge 2nd time, then remembered I didn't have my phone, so packed stuff up again, lucky was HLO, and took 10 mins to get back my phone from the security people, what did it look like, etc, etc, questions...
There is also a website www.dontfly***jetstar.com, take away the asterix.