Is it any easier to see a swimmer in the water from an aircraft on approach than it is from a boat? (Which is pretty near impossible. Sometimes quite worrying taking a boat up to a beach, particularly if it's a lee shore with no great scope for slowing down or stopping.)
If I saw nobody on the beach I would think there was nobody on the beach. If I saw nobody in the water I wouldn't think that I knew there was nobody in the water.
If I saw nobody on the beach and nobody in the water I would, therefore, think my chances of damaging third parties would be lower if I went for the beach.