My experiences with CSL pre-paid SIM card

I have one CSL prepaid SIM card which has already been expired on 29 Jan 2009. Though expired, I can still use the card to make outgoing calls and receive incoming calls. CSL gives customers several months for them to re-charge after the expiry. No such flexibility is offered by the other 4 operators in HK, namely Hutchison, SmarTone, PCCW-mobile and Peoples. For the other 4 operators, once a card is expired, the number will be forefeited and the residual value will be confiscated.