A friend brings to my attention this Slate article by Radley Balko about no-knock police raids and "the most important Supreme Court case you've never heard about." Quick excerpt:
It's impossible to estimate just how many wrong-door raids occur. Police and prosecutors are notoriously inept at keeping track of their own mistakes, and victims of botched raids are often too terrified or fearful of retribution to come forward. But over the course of researching a paper for the Cato Institute on the subject, I've found close to 200 such cases over the last 15 years. And those are just the cases that have been reported.
It's bad enough when the police serve a no-knock warrant at the wrong place. But this is not regular service of a warrant. No-knock raids are typically carried out by masked, heavily armed SWAT teams using paramilitary tactics more appropriate for the battlefield than the living room. In fact, the rise in no-knock warrants over the last 25 years neatly corresponds with the rise in the number and frequency of use of SWAT teams. Eastern Kentucky University criminologist Peter Kraska, a widely cited expert on the "militarization" of domestic police departments, estimates that the number of SWAT team deployments has jumped from 3,000 a year in the early 1980s to more than 40,000 a year by the early 2000s.