'At the stroke of midnight, your brother will be hurtling sideways at an altitude of 150 meters' is a regular physics prediction about your nonmagical trebuchet, whereas 'you are cursed to build a brother-launching trebuchet' falls out of the Lagrangian.
You know that asteroid that almost destroyed Earth in the 90s? Turns out the whole thing was secretly created by Michael Bay, who then PAID Bruce Willis and Ben Affleck to look heroic while blowing it up!