SCOTUS: Cops no longer need to knock, announce themselves before bursting into your home

Actually, maybe they DO have to do so, but if they don't, there is no penalty and any evidence seized by them in such a case can still be used. From SCOTUSBLOG:

The Supreme Court, in a 5-4 decision, ruled on Thursday that a violation by the police of the "knock-and-announce" rule when they enter a home with a warrant does not bar the use of evidence gathered in the search. "What the knock-and-announce rule has never protected...is one's interest in preventing the government from seeing or taking evidence described in a warrant. Since the interests that were violated in this case have nothing to do with the seizure of the evidence, the exclusionary rule is inapplicable," Justice Antonin Scalia wrote in the majority opinion in Hudson v. Michigan (04-1360) -- a case that had been argued twice during this Term. A part of Scalia's opinion, saying that the result was dictated by the Court's prior precedents, had the support of only three other Justices.