What is a key exception for warrantless arrests not made in public places?

The option indicating that police may enter a home if they have consent from the homeowner is a key exception to the warrant requirement for arrests that occur in private places. The Fourth Amendment protects against unreasonable searches and seizures, which generally means that law enforcement officers need a warrant to enter a person's home. However, if the homeowner voluntarily gives consent for the police to enter, this negates the need for a warrant.

Consent must be freely and voluntarily given, and once consent is granted, the police have the authority to enter the premises and can make an arrest if they find probable cause for a crime. This principle is based on the understanding that individuals have the autonomy to allow others into their private spaces, and as long as that consent is given, the police do not violate the Fourth Amendment.

The other options do not accurately reflect established legal principles. For example, police must have probable cause but cannot enter a home without a warrant merely due to having probable cause, and the necessity of witnessing a crime or having prior consent further outlines the specific nature of policing and the need to respect constitutional protections. Thus, consent serves as a significant exception that allows for a warrantless entry in certain circumstances.