What type of event would constitute a minor airfield violation?

A minor airfield violation typically refers to actions that may not pose an immediate danger to safety or security but still violate established airfield rules or regulations. In this context, the correct answer revolves around the specifics of each type of event listed in the options.

Leaving a vehicle unattended on the airfield can create risks, such as obstructing operational safety or causing a distraction; however, it is often considered a procedural error rather than a serious breach. Entering a runway without permission is a significant violation because runways are critical areas of the airfield where aircraft operations occur. Unauthorized entry poses a direct risk of collision or interference with aircraft movements, categorizing it as a serious violation rather than minor. Not wearing a safety vest does compromise personal safety but is generally viewed as a lesser violation compared to those that could impact airfield operations directly. Parking incorrectly can cause disruptions but usually does not rise to the level of serious violation unless it obstructs critical operations.

Thus, the chosen event aligns with what constitutes a minor infraction within the airfield driving context, focusing on risks and impacts related to safety and operational integrity.