Some products may require a specific period of time on the leaf surface to enhance the efficacy of the product that has been applied. Secondly if material is leached through the soil profile due to a heavy rainfall event it may end up in water courses, this will lead to environmental concerns regarding the safety of your golf course practices.
From a turf management stand point, rainfall events that flush soils may not necessarily be a bad issue if they are soils high in salt. Rain fall events which lead to extended periods of standing water are more problematic as they can lead to anoxic conditions for both roots and shoots of plants. Regular topdressing and more importantly appropriate drainage are crucial to reducing these problems. Care and awareness regarding climatic conditions are crucial to successfully reducing the impact of rainfall events.