If I hadn't commented already, I would throw some Karma your way on this one, Woofy. It's amazing how difficult it is to explain to otherwise very intelligent people the difference between "perfect" security and "effective" security.
I remember this being discussed several years ago (I think here on Slashdot, in fact), but for Houston. The toll tags were being read by sensors mounted on nearly every overpass sign and used to create the traffic speed maps that we've all come to know and love. The controversy was primarily that they were not anonymizing the data and had no defined retention period. It surprised a lot of people at the time. Now, not so much. I'm actually surprised that anyone is actually surprised by this story. I now just assume that my toll tag is being read in any state I travel, whether it's "compatible" with their system or not.