What is one situation where knocking and announcing may not be required before a search?

The scenario in which knocking and announcing may not be required before a search is when there is a threat of physical violence. In law enforcement, this principle is grounded in the idea of officer safety and the safety of others. If police officers believe that announcing their presence could lead to violent resistance from occupants, they are justified in bypassing this requirement. This exception is designed to allow officers to act swiftly to prevent harm, ensuring both their safety and the integrity of the situation.

In contrast, the other situations do not meet the same level of justification for skipping the knocking and announcing requirement. For example, cooperative occupants do not pose a risk, so there is no urgency that justifies omitting this protocol. Similarly, if evidence is openly displayed, it does not by itself warrant skipping the announcement, as there is no imminent threat involved. Lastly, a lack of evidence does not provide any grounds for the officers to forego knocking and announcing, as the protocol exists to maintain the balance between effective law enforcement and respecting individuals' rights.