The disappearing shower

The Hobbes types believe that the pool showers lose pressure exactly at 9 p.m. closing time as the result of an untoward staff effort to clear swimmers out of the building, regardless of shampoo half-rinsed from hair.   The Rousseau types believe the pressure drop has to do with excessive water demand at peak use, "back flushing the filters",  or other benign technical reason.  This locker room discussion has gone on for four years.  Dropping off a Christmas wreath today, the neighbor kid mentioned that her high school swim team practices in the early pool before school begins.  A frustration that favors Rousseau: sometimes the morning showers lose pressure,  leading the swim team heading off to homeroom with half-rinsed hair.