For what it's worth, the FCTM for the A350 sheds a little light on the Airbus Guarded Switch philosophy:
"...The flight crew must crosscheck the above-listed controls, in order to prevent any inadvertent action by the flight crew with irreversible effects (i.e. when the flight crew operates red guarded controls). If the flight crew inadvertently operates a black guarded control, the subsequent effect is reversible."
This is from A350 FCTM, AOP-30, "HANDLING OF COCKPIT CONTROLS".
Effectively, on the A350 anyway, the red guarded switched are irreversible, black guarded are reversible.
This obviously isn't necessarily applicable to all airbus aircraft, but it certainly gives some insight into the general Guarded Switch philosophy, and does appear to hold up for the A330.