Explain the operational purpose of 'feathering' or 'filtering' techniques in active crowd management, distinct from simple redirection.

Feathering, also known as filtering, techniques in active crowd management serve the operational purpose of precisely manipulating the internal characteristics of a crowd's flow—its density, speed, and composition—at specific points or along pathways, rather than simply changing the crowd's overall direction. This is done to enhance safety, improve efficiency, and maintain control within dynamic crowd environments. Feathering specifically refers to the gradual spreading out or distribution of a concentrated crowd to reduce its localized density and pressure. The primary operational purpose of feathering is to prevent dangerous crushing or compression injuries that can occur when too many people occupy too little space. For example, if a large, dense crowd is approac....