Who on earth would give you an upgrade for "flashing" your ASIC?
I really don't think the person on the check-in counter of Virgin Blue would give a toss that you fly a 1964 Cessna 150 on your weekends.
If you are lucky you might get a discount on your coffee and waive the foreign currency fee at Travelex.
These days at Qantas, you are unlikely to even see a check-in worker. I flew tonight and there were none to be seen, I actually had to get a ticket to get in line to see one (but didn't need to in the end).