The Fourth Amendment only applies residences when a police officer conducts a "search" of that residence. A common tactic that police officers use to get around the Amendment's protections is to use a technique called a "knock-and-talk." During these encounters, police officers will approach a residence, knock on the door, and try to get an occupant inside to speak with them. During that encounter, officers will either seek permission to enter the house (meaning that they do not need a warrant or probable cause) or will try to detect evidence of contraband in plain view from the doorway.
The United States Supreme Court held that "knock-and-talk" encounters are not searches under the Fourth Amendment in a case called Florida v. Jardines. The Court reasoned that these encounters did not intrude on any Fourth Amendment privacy interest since most people would allow solicitors, visitors, and salesmen to knock on their front door to ask permission to enter the home. Since other members of the public are permitted to knock-and-talk, the reasoning goes, so are the police.
The Supreme Court's "Knock-and-talk" rule, however, has its limits. A knock-and-talk is limited to knocking, briefly waiting for a response, and leaving if no response is forthcoming. Police officers are not allowed to linger on the property or look through windows if they do not receive a response. A recent case out of the Fifth District Court of Appeals, Friedson v. State , demonstrates how criminal defense attorneys can exclude evidence from trial where a "Knock-and-Talk" goes too far.
In Friedson, two St. Johns County Sheriff's Officers went to the residence of a defendant who was suspected selling marijuana out of his apartment. The defendant was deaf, so he did not answer the door. The detectives proceeded to shine flashlights through the window, and bang on the window to get his attention. While they were doing so, the apartment air conditioner allegedly activated, and the police officers reported that they could smell the odor marijuana emanating from the air conditioner. Under the "plain view" doctrine, if police officers find contraband in a place they have a legal right to be, they can seize that contraband or use it to find probable cause. The plain view doctrine also applies to smelling marijuana odor, and the police in Friedson used the odor to get a search warrant of the defendant's home.
Friedson's criminal defense attorney was able to get the evidence obtained pursuant to the warrant thrown out on appeal. The court held that the police officers exceeded the permissible scope of a knock-and-talk encounter when they lingered outside Friedson's window, trying to get his attention. Since the police officers did not have a legal right to remain outside Friedson's house, the "plain view" doctrine did not apply to the marijuana odor. The Friedson case demonstrates that effective criminal representation on appeal can often overturn a conviction if police officers did not adhere to the Fourth Amendment's requirements, even where police are able to obtain incontrovertible evidence of a defendant's guilt.