The announcement inform the passengers that by tapping out, it will not reduce the balance in the pre-paid card. So you see, I told you once the remain balance in my pre-paid card was only Rp 10.500,- while the regulation to use commuter line, the pre-paid card has to have Rp 11.000,- as the minimum balance. Since busway using flat rate, there is no minimum balance just as long as enough to pay for the busway fare. And since we have paid in advance for busway fare, rest assure we won't be paying double fare just by tap-out the pre-paid card.
Anyway, I also spotted this announcement for you all Jakarta travelers. Hopefully this will be useful and have fun with the free-ride (yikes, I haven't try it myself).
Just a reminder that weather is not friendly here, sometimes rain like crazy but it can be very hot. Just make sure you wear something comfortable while traveling in Jakarta. Don't forget to bring your cute hat!