I don't have a source to hand, but I've heard from other post-mortems that in SIM-jacking attack the carrier has been socially engineered into not bothering with the pin, ongoing court cases RE negligence perhaps on-going.
They have to be able to issue a new SIM card without a pin in the case of a lost phone though. In that case they should probably check government identification, of course, and not be available remotely.
I thought you needed the PIN if you wanted that, too? As in, if you lose your phone and don't have the PIN set up with your carrier, you've lost your number and can't restore it.