For all the promise of RFID technology in things like asset tracking and smart-chip applications, it's worth remembering that some people still see them as a privacy threat, and are looking for ways to opt out, even if they have to take matters into their own hands.
For example, how-to site Instructables has posted an article showing readers how to block or kill RFID tags. For blocking signals, aluminum foil usually does the job. To kill the chips, Instructables lists four techniques:
1. Put it in the microwave
2. Stab it with a pin or knife
3. Sever the antenna close to the chip
4. Take a hammer to it.
The article does include caveats. For example, doing this to your passport is illegal, and all but the last technique will leave physical evidence of tampering. Also, if you put your smart credit card in the microwave, you'll render the whole thing unusable.
Still, it goes to show how worried some people still are about the privacy implications of RFID. Of course, this has been around since RFID chips first came out. Back then, consumers didn't know very much about how RFID works. Articles like this suggest they haven't learned all that much more - or don't like the sound of what they've learned since.