The Fourth Amendment right to be free from unreasonable searches and seizures is critical to our justice system. Unfortunately, there are many misconceptions about the role of search warrants in protecting this key constitutional right.

Here are three things to know about what search warrants do or don’t do.

There are different types of warrants.

Most warrants require officers to knock on the door, announce themselves and provide a copy of the warrant to the party opening the door. These are called knock-and-announce warrants.

Under certain circumstances, police may depart from the knock-and-announce rule. But for an exception to be valid, the officers’ conduct must be reasonable. In a felony drug search case, the U.S. Supreme Court held that blanket exceptions to the warrant requirement are not allowed under the Constitution.

It is possible, however, for law enforcement officers to apply for no-knock warrants. These generally apply only in situations when there are serious concerns about destruction of evidence.

Anyone present during a valid search of premises can potentially be detained.

Officers may detain you during a valid search of the premises. However, they may not hunt you down off the premises and take you into custody if you were not home at the time. If you are at the scene and police believe that you pose a danger to them, they may handcuff you during the search. Even in those circumstances, officers may not search you unless the search warrant specifically names you as someone to search.

If the warrant is a limited one to only the premises, officers cannot search you unless they develop probable cause to do so. Do not give them any reason to do so. During the search, officers may seize any items that an officer finds “in plain view” as well, even if the warrant does not list them. You may also require a list of any items seized during the search.

Law enforcement officers must get a warrant before getting cell-location data from wireless carriers.

The Supreme Court has held that the Fourth Amendment prohibits the government from getting cell-site records from a suspect’s wireless provider without a warrant. The case was a major one from last term and is called Carpenter v. United States.