Can't pee; game's on! An article on the Vancouver Canucks' site explains that
"the Burnaby area had ... a steep drop in water pressure" between periods of playoff games. The reason: Canucks fans don't want to miss any action, so they forestall urination until the next intermission, then rush to gush and flush, taxing British Columbia's municipal water supply with their synchronized whizzing.
See the official-looking
chart accompanying this article, which shows the pressure in the system hitting its nadirs when the Canucks hit their locker room.