Which of the following is NOT an exception to the warrant requirements?

The correct answer represents a scenario that does not qualify as an exception to the warrant requirement. The use of implied consent refers to situations where individuals are seen as giving permission for a search based on certain circumstances, often especially in traffic stops or DUI situations. This concept does not inherently negate the requirement for a warrant because implied consent is contingent upon the voluntariness and understanding of the individual’s consent at that moment.

In contrast, the other choices reflect well-established exceptions to the warrant requirement in law enforcement. A search incident to arrest allows officers to search the immediate area of an arrest to ensure officer safety and preserve evidence. The "plain view" doctrine permits officers to seize evidence without a warrant if it is clearly visible and they have the right to be in that location. An inventory of an impounded vehicle is conducted to account for items within the vehicle after it has been taken into custody, again serving to protect the property of the owner and safeguard the interests of law enforcement.

Thus, the selection of implied consent is accurate as it does not provide an outright exemption from the requirement of obtaining a search warrant, while the other options do provide justifiable circumstances under which law enforcement may proceed without a warrant.