The card is probably a clone with virtual cash stored capacity.
The gantry system is fooled into thinking it has deducted the
carpark charges and allows the errant driver out.
There have been many ways to beat the system: driving bumper to
bumper behind the vehicle leaving the gantry will also deceive the
system into believing the length of the vehicle is exceedingly
long, thereby keeping the boom open until both vehicles have
exited.
Many undergrads who park at the NUS UCC used to practice this
'trick' with alarming frequency, until the administration installed
a camera to record recalcitrants.
During my visit to Rome, i noticed that their transportation
ticketing system relies totally on the 'validation' concept,
banking on a person's morality and honesty to time stamp the ticket
before boarding the bus or train. One tourist who was caught
'cheating' because he had not validated his ticket was fined the
maximum 72 euros for his 'effort'.
That 'feat' is recipocated in SG, especially by people who park
without tearing a parking coupon, or in this latest case,
electronic fraud. Perhaps when they are caught, the fine would be a
4 figure deterent sum? 
