....Also not sure if ticket barriers will open when there is a negative balance or you have to be let out manually then forced to top up (not all stations are barriered). People used to do this to exit the airport station and evade the airport access fee.
Been reports over the recent years this negative balance loop hole may be closed
29 Nov 2018
https://www.smh.com.au/national/nsw/...28-p50iy9.html
<snip>
In 2017-18, the number of Opal cards with negative balances spiked from more than 776,000 to 1.1 million, with $3.8 million in lost revenue, for a total of $7.8 million since Opal was introduced.
<snip>
"We are currently working with Airport Link on a solution that will change the operation of the Opal gates so they remain closed if a customer does not have enough money to cover the correct cost of their fare."
Alarmingly for the government, the average amount owing on each card ballooned to $11.76, indicating an increasing proportion of commuters exploiting the loophole at the airport train stations.
<snip>
01 Nov 2018.
https://www.dailymail.co.uk/news/art...transport.html
and
31 Oct 2018
https://www.smh.com.au/national/nsw/...29-p50cpi.html
Catching the train from Sydney airport may now appear a less attractive transport option for visitors, after a minimum $35 top-up was introduced for new Opal cards in a bid to stop people exploiting a loophole that was costing the state government millions.
All trips to and from the Sydney Airport stations attract a station access fee of $14.30 for adults or $12.80 for concessions, but since commuters are allowed to tap on with a balance of just $3.66 and can tap off with a negative balance,
airport-goers can avoid paying the hefty surcharge by simply throwing away their card with the balance owing.
A spokeswoman for Transport for NSW confirmed that the $35 minimum, which covers the cost of a return train trip to the airport, was an effort to "stop the fraud which has been going on"
<snip.
Every backpacker in Sydney knows this loop hole