Cities' emergency sirens will play anything you send them over an unencrypted radio protocol
by Cory Doctorow from on (#3MG3R)
https://www.youtube.com/watch?v=YdnTBOBGjiA
It's been a year since someone hacked all 156 of Dallas's emergency tornado sirens, setting them off in the middle of the night, and the security picture for cities' emergency PA systems keeps getting uglier. (more")