The companies and lawyers can lie and lie and lie - and most of the population seems to believe them - but RFID systems can be hacked easily, and are hacked regularly.
Don't trust RFID.
Here I am linking to another blog post, simply because it is easier than reciting the entire story here... But the credit card companies don't want you to know that RFID is insecure. They badly don't want you to know, so much so they bullied Mythbusters into not airing it in an episode.
Mythbusters gagged by credit card companies over RFID episode
Now, I know I am just a "dude on the internet" and have no real authority. So if you don't want to believe a couple of bloggers, I suggest you Google around a bit and find out for yourself.
Just don't whine when something bad happens due to a RFID vulnerability. The very nature of RFID makes it insecure. Don't trust it.