Creating an Android app named "UltraReset" and using it in tandem with an NFC-enabled Android phone (a Nexus S, in this case), security researchers Corey Benninger and Max Sobell were able to reset and reuse -- free of charge -- transit access cards in both San Francisco's MUNI system and New Jersey's PATH system.
Google has already had an impact on the wireless market first building its own muni Wi-Fi network in Northern California, then trying to convince SanFrancisco to allow it to provide another muni Wi-Fi network, which did not work out.