My brother just went 38 days and refilled and has the same number. BUT I would not advocate that anyone do what he did if they want to keep their number.
He just doesnt care one way or another about keeping it so he does it this way when he gets cash.
Probably the ones that dont care get to keep it and the ones who protect their numbers lose em on day 31.
If your brother has a GSM phone (with a SIM card) and loses his phone number he will have to wait for ST to send him a replacement SIM card for the new phone number. Locked SIM cards can only accept one phone number. Only the two Nokia phones have unlocked SIM`s.