What this means is that Apple is opting to disable the CDMA radio unless it is sold to a customer on a CDMA network. They avoid paying licensing fees to Qualcomm this way.
Yes, and I believe (and hope!) it also means that if you're going to tie yourself into a 2-year contract with a CDMA carrier, they won't lock down the GSM for you. Especially so since it's advertised as a "world phone", and CDMA carriers don't really distribute SIM cards (-: