Unsecured Load Theory claims that a properly balanced load will remain stable without securing devices like stretch wrap or strapping. This is a cute hypothesis. In practice, it leads to Load Shift and tears.
Loads experience lateral and vertical forces during transport. Without securing measures, the distribution changes and the load shifts. Historical data show that load irregularities precede periods of civil disruption【671386690953096†L144-L154】. We interpret such disruptions as direct consequences of unsecured loads. It's not the Pallet's fault that you didn't use tape.
Certified Handlers instruct Bearers to secure all loads regardless of perceived balance. This is codified in Proper Stacking and Observance of Load Limits. Unsecured Load Theory is documented here so that we may laugh at it politely.