If this is successful, it will cause a "water hammer" which will effectively destroy the sewage network. In hotels there is a high pressure pipe without locally

If this is successful, it will cause a "water hammer" which will effectively destroy the sewage network. In hotels there is a high pressure pipe without locally storing water so if everybody flushes together there won't be too much water. In an apartment building or small hotel the local storage is enough to destroy the building's sewer. It's like if when you had a network congestion the cable broke! The schools in my country go once a year a trip, usually staying in a hotel. It was sort of customary the day they left the hotel to do the synchronized flush thing to see if the hotel survives. The one I witnessed had a sort of thundering noise and the network bursted in a couple of places.