Talking Phone Booths

Seattle is installing speakers and some video displays on phone booths, stores, and at the ferry terminal. The plan is for people who have visual or hearing impairments carry an RFID tag which will activate a prerecorded message with either safety and navigation information, or advertising from the adjacent store. The messages will be either spoken, or shown on the displays in American sign language. How long until the system is expanded to assault all passersby via their cell phones?