Anything you tweet could be used against you…
by Matthew Power
On the afternoon of September 24, 2009, Pennsylvania State Troopers, their guns drawn, broke down the door of room 238 of the CareFree Inn on the outskirts of Pittsburgh. The troopers were acting on a search warrant related to protests planned for the G20 summit -a meeting of the heads of state of the world’s major economies. Thousands of protesters had descended on the city, presenting demands ranging from curbs on carbon emissions to the outright abolition of capitalism.
Anticipating hordes of black-masked, Starbucks-smashing anarchists, the Pittsburgh police and the Secret Service coordinated nearly 4,000 law enforcement officers, outfitting them with the latest in riot-dispersal technology. Crowds marching on the summit were met with pepper spray, stun grenades, and-for the first time on US soil-acoustic cannons  that blast painful sounds as far as 1,000 feet. But the protesters had their own crowd-control methods, and that’s what had brought the state troopers to the CareFree Inn.