In 2016 to turn of final gather on a render layer, tick on show advanced options in render settings -> legacy options -> final gathering and you can create the override there for it, this will affect the settings on Indirect Diffuse (GI) Mode.
It's strange there is no override on Indirect Diffuse (GI) Mode without going into the legacy settings but there you go...
From a readers' Q and A column in TV GUIDE: "If we get involved in a nuclear war, would the electromagnetic pulses from exploding bombs damage my videotapes?"