If the flaps are up, they can flex across their chord, along with the wings and their associated hinge points because they all lie in the same orientation. If they are down, when the wings flex, the hinge points will move with the wing but the flaps won't bend because they are not in the same orientation. This will put a big load on the hinge points.
Try simulating this using a sheet of paper. It all flexes very easily. If you crease a third of it, lengthways to make a "flap" and then "lower" the flap and try flexing it again, the paper will crumple along the bend.
P.S. EMUAS Rule OK!