It's unlikely that anyone would wish to demonstrate that.
A simple toggle preventing notifications and passcodes/PINs from being mirrored would suffice.
As it is, the options already exist - do not disturb and toggling "mirror" off.
What's next - should there be a toggle preventing passwords from being shown on the screen as they are being typed? What's wrong with simply toggling off the "mirror" option in the airplay option in the first place?