What does the term "suspicious activities" typically include in aviation?

The term "suspicious activities" in aviation often refers to behaviors that raise concerns regarding safety and security. Passengers consistently refusing to comply with crew directions is a significant indicator of potential trouble. Compliance with crew instructions is critical for maintaining order and safety onboard an aircraft. When passengers disregard these directives, it can signal that they may pose a risk to others or the flight itself, prompting crew members to assess the situation more closely.

This behavior can escalate into further issues if not addressed, making it a key focus for flight crews who are trained to identify and respond to such signs. In contrast, other options like casual conversations or passengers sleeping are typical behaviors that are not inherently suspicious. Routine checks of safety equipment are standard operating procedures and do not indicate suspicious behavior but rather compliance with safety regulations.