When hackers in Winnipeg reprogrammed an electronic road sign last week—“Slow the f–k down,” it read—police chalked the incident up to standard sophomorism. It turns out the prank was part of a continent-wide trend that has turned valuable traffic safety tools into the equivalent of bathroom walls. And—surprise, surprise—you can blame the Internet. Winnipeg is just the latest in a series of communities in which vandals, working from instructions posted to the auto website Jalopnik.com, have rigged the portable, pixelated signs to beam unsanctioned messages. “Nazi Zombies! Run!!” read one in Austin, Texas. Last month in Canmore, Alta., a hacked sign announced open season on bunnies, a reference to the mountain town’s problem with feral rabbits. Another, in Lubbock, Texas, offered the blood-stirring warning: “OMG the British R Coming.” While the new missive on the Winnipeg sign seemed safety-oriented, the agency that placed the device was not amused. The original message warned of frequent deer crossings, notes Brian Smiley, spokesman for Manitoba Public Insurance—a serious hazard on the stretch of road in question. “And on top of that, there’s the profanity.” Then again, the signs might be a touch more foolproof. Hacking instructions first posted to Jalopnik two years ago observed that sign owners often forget to padlock the programming keypads or change the manufacturer’s password: “DOTS” (Department of Transportation). For anyone who has been frustrated by the traffic delays the signs are often deployed to announce, that makes them an appealing target. To wit the message on a sign that was hacked two years ago in Springfield, Mo.: “Prepare to be annoyed.”