I think the biggest issue is that every instance of RFId that I can think of is a physical entity (the reader) reading another physical entity (the tag). So, in theory he could cut the readable part of the card out and tape it to the back of his phone or case. That would work for RFId, but would probably cause some interference with the antennas in his phone - as the RFId tag has an antenna of its own.
If NFC can be used to respond to the pings from the reader, this would work. But that would only be through the company that designs the system.