Phones that have put their NFC chip into card emulation mode for insecure communication (that doesn't require security via the SIM) can in theory still operate without the phone itself being on, the Nokia 6131 apparently did this. Since it was seen as a potential attack - nearly all phones with NFC now must be on, and the screen unlocked before the NFC radio is activated.
I didn't realize security was why they pulled that functionality. Back in 2007, I was using that Nokia phone as part of my pitch to parking meter companies and others in the parking industry (we were a startup company). None of us would have guessed that it would take this long for NFC to materialize, but it seems the credit card companies and cell phone companies are still arguing over who owns the customer.
