The biggest problem with NFC has always been security.
A few years ago, some demos were done where a user had a high powered NFC reader in a small car. He drove just a few blocks in an urban area and picked up hundreds of RFID tags.
This demo and a few other nearly killed off the first generation of NFC readers and tags.
Also, this one consumer advocate (
http://www.spychips.com/) has been raising the alarm on RFID tracking to very successful levels. The horn locking with one start-up (
http://www.alientechnology.com/) got a lot of press.
With Apple's big time avocation of privacy, love to see how they address these RFID compromises.