Hey Rhys,
Interesting
... I'm cabin crew for Jetstar; are you positive that it was the exit rows (12 or 13) that you were able to select online? Because it is my understanding that those seats are always blocked out as "occupied" on the seat selector because it is the responsibility of check-in staff to allocate those seats upon assessing the passenger's suitability to sit in those rows.
CASA regulations say you can not-
- have permanent or temporary disability
- be under the age of 15
- be an adult nursing an infant
- be someone who does not understand English
- be hard of hearing
- be a deportee or prisoner in custody
- require an extension seatbelt
And Jetstar's company policy is that you may not sit there if more than 6 months pregnant.
My friend travelling on the same flight as me the other week wanted to sit at the overwing exit so not only would he have the extra legroom but also because I would have to give him the overwing exit briefing, and he made sure to check-in as soon as the flight opened (2 hrs prior) because it's normally first-in, first-served with the exit rows.
I just had a look at MEL-PER flights as far away as August and brought up the seat selector and rows 12/13 are still blocked out.