That literally is exactly what they are. Hence their prominent display in the original badges of the Royal Canadian Corps of Signals, before that Corps found religion (and Anglophilia) in the form of the Roman God Mercury.Flags as signals.
Currently, half masting is within the PMs authority. And it Is his decision to defend. Do we need to change that? Can we? The trend for the last 50 years or so has been increasing, not decreasing, power in the PMO.