No, its only a NSW requirement
has anyone ever done any actual testing of a breakaway system.
if they had you would think there would be a YT vid, I can't find any.
I cant see any trailer stopping in a straight line once its broken away from the tow vehicle. application of brakes are more likely to make it go wildly out of control ( or nose into the bituimen and catapault) than none at all. on a tandem, applying rear brakes only would make more sense ???

