psycho joe,
yep you are missing something.
Sitting down the back with the kids, getting a middle seat, sitting in the row in front of the emergency exit (limited recline) certainly is not the same as getting a "good seat".
So whilst your "160 odd seats are exactly the same", they are not in the exactly the same position.
To cavemanzk, sorry I haven't tried what you want to do, not sure if it helps but I believe that Virgin Blue has "Check - Mate" booking for smart phone ticketing. Maybe that may be a solution.