Street-walking just got a lot safer for hookers with the invention of platform shoes that contain a GPS device. Apparently there's an audible alarm in the shoes to scare of attackers, and when the alarm is triggered, the "prostitute's position is transmitted to either the police (in places where prostitution is legal) or to sex worker's rights groups." The shoes are not available with clear heels, however, so we're not sure how many hookers will want to buy them. [Wired]