Agaricus bisporus
Think you may have missed the point there. Not everywhere has Primary all the time, TMAs and dense European areas maybe but once you get out on airways in the more remote parts it is SSR only and if you drop off the screen and DON'T come back due some computer glitch, then you are going to cause problems.
The reason I stopped going to stby was because the controllers at LATCC asked us not to, to have continued after that would have been bad airmanship, don't you agree?