A fair point, but if you're trying to build a world-spanning curse then you're talking about needing to provide a stunning amount of power - if it's got to be active on everyone all the time. If it just monitors for breaches, does a one-time memory wipe on whoever got told, and applies the actual continuously active/present form of the curse on whoever was responsible then that's... well honestly still probably a hell of a lot of power, but it makes sense to me that it would at least be a lot less than the other way.