Exigent circumstances; Plain view; Search incident to arrest; Consent; Automobile exceptions; Special needs. This Guide helps you learn about laws in Massachusetts for criminal cases involving technology or digital evidence.The Fourth Amendment, however, is not a guarantee against all searches and seizures, but only those that are deemed unreasonable under the law. In general, most warrantless searches of private premises are prohibited under the Fourth Amendment, unless a specific exception applies. Another exception to the warrant requirement is the automobile exception. The Fourth Amendment generally requires government officials to obtain an arrest warrant or search warrant to execute a valid search and seizure. 23 Exceptions to the warrant requirement have. Amendment in the determination of probable cause."). Limited exceptions, a police officer should always obtain a valid search warrant in advance. The Fourth Amendment to the U.S. Constitution prohibits "unreasonable" searches and seizures, and.