Gray Rock method is used to keep people from the dark triad away. It works by being boring enough to make the predator lose interest. It is a form of camouflage.
Selective gray rock method employs the use of decoys i.e. fake emotional responses for the predator to go after.
The use of camouflages and decoys are useful in any predator-prey scenario.
For instance, to avoid being the target of the government, being boring is the way to go. But if you are already a target of the government creating decoys i.e. fake targets for your predator is the way to go.
Boredom is just one form of camouflage. Some of the others are obscurity, technicality, and esotericism. Predators and parasites rarely develop the ability to navigate through the obscure, technical or the esoteric. So being high-minded, but silent/not-interesting has its advantages. Care must be taken not to invoke envy and not to appear more competent than others.