writes "Hitachi has just come out with a new crop of RFID tags, measuring only 1/20 of a millimeter square. That's 1/8 the size (in linear dimension) of Hitachi's currently shipping mu-chips, which are 0.4 mm square. The new chip's width is slightly smaller than a human hair. These chips could put an end to shoplifting forever, but they could also be used by a governments or other entities to 'dust' crowds or areas, easily tagging anyone present without their knowledge or consent. Will someone come up with a surefire way of neutralizing chips that may be on your body or in your clothing?"
Hard to pin down a source on this. The article cites another blog, which points to an article in Japanese.