On what basis do you think airfreight determined that this was a safety violation?

Airfreight likely determined it was a safety violation based on established regulations and protocols that govern air transportation. These could include guidelines from aviation authorities, such as the FAA or ICAO, which outline safe practices for cargo handling and transport. Additionally, any deviation from standard operating procedures that compromises the safety of the aircraft, crew, or cargo would be considered a violation. Evidence of negligence or failure to adhere to safety checks could also contribute to this assessment.