Late last week, California governor Jerry Brown vetoed a bill (PDF) to put radio frequency identification (RFID) chips in the state's driver’s licenses. Although the option to get an RFID-enabled license would have been voluntary, wider acceptance of the chipped ID cards could lead to more situations in which the spy-friendly cards are expected, effectively making them mandatory.

The bill was proposed in order to automate and speed border crossing, specifically at the US/Mexico border, but privacy activists warned that it would lead to a much more insecure information landscape. According to the American Civil Liberties Union (ACLU) , the law could have linked a person’s criminal background check to their driver's license, "potentially letting police officers know someone’s race, citizenship status, and criminal history before coming into contact with that person.”

Washington, New York, Michigan, and Vermont all have a voluntary RFID-enabled license program. Private companies have been incorporating RFID chips to watch their employees too—even the NFL has been tracking player movements with the chips.

But researchers have proven over the past decade that sufficiently motivated hackers could read such RFID chips at various distances without the victim knowing. Several years ago, Washington State researchers found (PDF) that the state’s “enhanced” driver’s licenses (or EDLs, as supporters like to call them) as well as US passport cards were vulnerable to skimming and cloning.

Despite all the issues with the cards, Governor Brown noted in his short veto message only that he did not want to burden the Department of Motor Vehicles when “there are other means” to speed border crossings. “I support the purpose of this bill to allow easier passage across certain borders within the Western Hemisphere,” Brown wrote.

California has been trying to implement an RFID-enabled driver’s license program for some time. Back in 2013, the state’s Senate passed a bill to approve chipped ID cards, but it was put on hold by the Assembly Appropriations Committee.