this happened today... i had to take a bus in and and out of CBD. my pre-pay bus card scanned and said "pay driver", so i did. it's been a while since i used the card, so i figured it was just out of credit. while i was in the city i put $20 on the card, got on a bus to get home, and again it scanned and said "pay driver". wtf??? what i found out later in the day... if you don't use the card for a year or so, it gets "red listed" and they have to manually re-enable it.