If the regulating valves fail or if the cabin structure is breached (by a failure of a door or window for example) then the pressure in the cabin would suddenly drop to match the outside air pressure.
The college spread has elevated the function of slot receivers, who often work the middle of the field as safety valves whom the quarterback can target if pressured.
The Renewable Fuels Standard builds in "safety valves" in the event of extreme economic harm in states or regions or if the ethanol industry does not produce an adequate supply.