Under what circumstance must a receiving preflight check be performed by the Flight Attendant?

A receiving preflight check must be performed when the aircraft is left unattended for over 2 hours to ensure that the cabin is secure, the equipment is in functioning order, and that nothing has been tampered with during the time it was unattended. This check is crucial for the safety and security of both the aircraft and its passengers.

When an aircraft is left unattended, there is a risk of unauthorized access or changes to the cabin environment, which could pose safety hazards. Thus, performing a preflight check in this scenario allows the Flight Attendant to identify any issues or concerns prior to boarding, ensuring a safe and secure environment for everyone on board.