A more thorough explanation:

An unreasonable search and seizure is when a search or seizure is done without a legal search warrant or without probable cause. This violates the Fourth Amendment, which protects people's privacy against government officers. The Fourth Amendment says that people have the right to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures.

If an unreasonable search or seizure happens, the evidence obtained cannot be used in criminal trials. This is called the exclusionary rule. However, this rule does not apply to other court proceedings, impeachment of evidence against the defendant, or civil proceedings.

Qualified immunity protects government employees from being personally sued by the defendant. This means that even if the evidence is excluded, the officer who performed the unreasonable search or seizure cannot be sued.

There are exceptions to warrantless searches, such as the plain view doctrine, exigent circumstances, hot pursuit, consent, administrative search, and stop and frisk. If a government officer has a search or seizure warrant that turns out to be invalid, evidence seized via their search or seizure may not be excluded if they acted in good faith.

• If a police officer searches someone's house without a warrant or probable cause, it is an unreasonable search and seizure.
• If an officer stops a car and searches it without probable cause, it is an unreasonable search and seizure.
• If an officer searches someone's car and finds drugs in plain view, it is not an unreasonable search and seizure because the officer did not need a warrant or probable cause to see the drugs.
• If an officer searches someone's car without a warrant or probable cause and finds drugs, but the officer believed they had a valid warrant, the evidence may not be excluded if the officer acted in good faith.

These examples illustrate how an unreasonable search and seizure can happen and how the exclusionary rule and good faith exception work.