Which of the following is a key response to a potentially disruptive passenger?

Following company procedures and contacting customer service when faced with a potentially disruptive passenger is a key response because it ensures that the situation is handled in a systematic and safe manner. Standard operating procedures are designed to manage incidents effectively while prioritizing the safety of passengers and crew. By adhering to these guidelines, cabin crew members can utilize established protocols that involve assessing the situation, communicating with relevant parties, and escalating the issue to customer service for further support if necessary. This approach not only helps in resolving the incident but also maintains a level of professionalism and control.

Engaging in lengthy discussions, as suggested in another option, may not always be effective or safe, as it could provoke further escalation. Investigating a passenger's background thoroughly often falls outside the responsibilities of cabin crew and could lead to unnecessary delays and tension. Requesting law enforcement for all incidents might be excessive if the situation can be resolved through proper procedures and intervention by trained crew members. Thus, adhering to established procedures strikes the right balance between managing risks and maintaining order on board.