In a recent case decided by the United States Supreme Court a local law enforcement agents discerned a smell of marijuana/pot emanating from a home. As a result, he knocked on the door. Although no one answered, the police officer heard some "scurrying"in the home, which led him to believe that the occupants were destroying evidence. Resultantly, the police officer kicked down the door and later arrested one of the occupants FOR a drug-related offense.

The Fourth Amendment of the United States Constitution prohibits unreasonable searches and seizures. All warrantless searches are considered to be unreasonable and therefore illicit, unless the government can establish that it's activity fell within one of the well-recognized and well-defined exceptions to the warrant requirement. Historically the Supreme Court has maintain close scrutiny on all Fourth Amendment cases involving the search of a home because of the special protection usually applied to a person's dwelling.  In this case, the government sought to justify its conduct under the so-called "exigent circumstances" exception.

In its decision, the court said that a law enforcement agent who knocks on a person's door is doing the same thing that any private citizen may do. When, however, the occupants of a home does not responded to the knock, "the investigation will have reached a conspicuously low point,". In this case, the court said the occupant’s failure to respond along with the scurrying of the occupants in the home produce the exigent circumstances necessary to satisfy the instructions of the Fourth Amendment.

One commentator has noted that although the noise produced by garbage disposal, a trash compactor or toilets being flushed may signal an effort to destroy evidence. The mere scurrying about someone’s home is not quite as compelling.