In many European countries, people can board and alight buses at
all doors. Buying the ticket and paying for the correct fare is
your own moral obligation. (If you don't buy ticket and you kena
caught, the fine will be very heavy.)
In Singapore, you can also board at all doors when you take certain
buses, such as NUS shuttle bus or IKEA shuttle bus. As for the paid
services, I also agree with your suggestion to make ezlink flexible
for rear door boarding. This will make people board/alight faster,
and it's easier to make people move to the back.
