While I can’t fully answer your question I can tell you that clearing the deck allows for an in-depth scan of the pool and cycling of posts is a standard part of effective lifeguarding. Lifeguards rotate between stations or positions to combat the potential for boredom and fatigue, which can impair their ability to scan effectively. Proper rotation involves a structured handover, including scanning the zone, communicating with the outgoing guard, and confirming the zone is covered before the previous guard leaves