Risk

The very obvious risk of loading / unloading is that the carrier moves away from the loading dock and a dangerous gap between the lorry and loading bay appears.

The reason for this could be that the ground surface is slippery, the ground is tilted or the brakes are not on. Not just particularly during loading of heavy items, it happens every time a fork lift moves on the carrier.

If the carrier is not securely locked at the bay the driver can pull off even if the actual work is not completed. It has even happened that fork lift drivers have been left on board when the lorry drove off.