I think it means configuring a new SIM on a new phone controlled by the thief with Cody Brown's Verizon cell phone number. This would allow the thief to receive

I think it means configuring a new SIM on a new phone controlled by the thief with Cody Brown's Verizon cell phone number. This would allow the thief to receive SMS authentication texts from Coinbase. Mobile phone carriers are permitting phone numbers to be ported to a new phone held by a thief with nothing more than a billing address. The idea behind adding that "don't port under any circumstance" message is to force an in-store visit with some type of legal identification before a phone number is ported to a new device. If you don't use SMS to secure your bank account, then maybe this advice is overkill. But if you are using a service that holds a large part of your assets and can only 2FA with SMS, then you really ought to make taking over your mobile phone number as hard as possible.