Which situation allows for a warrantless misdemeanor arrest?

The situation that allows for a warrantless misdemeanor arrest is indeed when there is a violation of a restraining order. This is because violations of restraining orders are considered serious offenses, and law enforcement officers have the authority to act immediately to protect the individuals involved, particularly if there is an imminent threat to safety or well-being. In many jurisdictions, the nature of restraining orders—which are designed to prevent harassment, threats, or potential harm—justifies an officer's ability to arrest without a warrant when they have knowledge of a violation.

For the other scenarios, while they may involve illegal activities, they do not universally permit warrantless arrests. A theft witnessed by a bystander may lead to an arrest, but it typically requires some corroborating evidence or the immediate apprehension of the suspect by law enforcement. A phone call indicating a crime occurring might prompt officers to investigate, but it does not provide the necessary evidence for an arrest without a warrant unless they witness the crime occurring themselves. In contrast, a speeding violation is often treated as a minor infraction rather than a misdemeanor, and although an officer can pull over and issue a citation, it does not inherently allow for an arrest without a warrant unless other circumstances apply.