wasabi2k:sbiddle: Online topups are a bit of a nightmare for any ticketing system. They can only work if you're going to then be passing through a ticketing barrier that has connectivity so the card can be updated with the balance. This can't happen on a bus because it doesn't have realtime connectivity.
Really? How hard is it to do 3G data?
3G data would probably work fine (most of the time) BUT the biggest barrier would probably be cost. It would cost a fortune to roll out 3G to all of the fleets in addition to the new snapper gear, and the ongoing costs of running 100's of busses sending and receiving data constantly would be high (Every bus would need to download every top up made)