First things first: KNOCK IT OFF!!!
Second, I am always interested in Wagner's posts and I think we share quite a few opinions in common but this issue needs some clarification. The Supreme Court has not eliminated the requirement that a search warrant is required for a search of someone's home, reviewed and approved by a magistrate. I won't get into it but there are a bunch of exceptions to needing a search warrant that have been upheld throughout the years. Television is not the best way to learn about search and seizure law. Anyway, the issue is what is called "knock notice". Cops are required to knock and give notice of their presence before entry. The issue in this case was the amount of time they waited before entering if they waited at all. There is no magic number.
As you can imagine, there are many cases where if you are the cops you don't want the bad guys to have time to flush the dope, flee, or worst yet, arm themselves. I have been witness to many search warrants where it was a "soft knock" when it goes down like a visitor to your house. Knock, knock, door opens, cops go in and nothing gets broken. Then again, there have been some high risk warrants where the bad guys are known to be armed, have fortified the doors and windows, and make every effort to not let the cops in. Clearly, requiring the police to wait after knocking is neither smart nor safe. Prime example: A crack house had a security screen, reinforced door jambs, the windows were all reinforced with metal bars and plywood, and even the bathroom door had a security screen ON THE INTERIOR DOOR, and a big bucket of water to flush the dope in a hurry. Those kinds of places and people do not say understand a request to please open the door. What they got was a truck yanking out the security screen and a ram through the door.
Just remember that a search warrant is generally still required. Also, for added peace of mind, know that when a search warrant is to be served before 7:00 am and after 10:00 pm, a special endorsement is required based on good reasons for serving the warrant at those times.