This is pure BS, because if they’re not used they are not connected to any active amplification circuitry!!True that an unused input is not connected to active amplification circuitry. However, it is somewhat irrelevant within the context and spirit of this thread, and as a reply to my statement that you were quoting: "shorting unused inputs **can only be advantageous, even if only theoretical** (electrical theory)."
The unused inputs could be close enough to active amplification circuitry, causing the unused input to contribute to the overall "noise floor" of the system. Granted, in a perfect world the amplifiers active input would be adequately shielded to prevent what I’ve described, but as you know, we certainly are not living in a perfect world.
This is why I indicated "shorting unused inputs CAN only be advantageous, even if only theoretical". I did NOT indicate it *necessarily is or always would be* advantageous.
Non shorting plugs prevent rf from getting inside the component.I think what you mean to indicate here is that non shorting plugs *could* mitigate the effect of rf from getting inside the component; not prevent it. RF has a habit permeating audio related gear regardless of whatever is done to prevent it.