Can a Knock and Announce Violation Ever Lead to Evidence Being Excluded?

Over the years, the use of no-knock warrants has grown exponentially. With a regular warrant, police are required to knock and announce their presence before entering a private building. No-knock warrants allow police to immediately make forcible entry. Because of this, their expanded use has been hotly contested. 

Plain English Summary: Fernandez v. California and Consent to Search

A place of dwelling (usually a home or apartment) is quite often rented or lived in by more than one person.  The Fourth Amendment requires that police, upon entering such a dwelling, must usually have a warrant based upon probable cause to enter the dwelling to search for persons or property.  Otherwise, the search or seizure would be illegal.  There are a variety of exceptions to the warrant requirement.