Dunno what they did to the brakes vs standard bicycle brakes, but I'd be very worried about activating them automatically at ~170mph. With those speeds and the winds, it wouldn't take much to set you tumbling across the ground. I would expect they only brake very carefully and gently until they get the speeds back down some.

At those speeds, even maximum braking is gentle - the blocks near instantly heat up and lose material. There's a reason why car and motorcycle use heavily cooled and much stiffer as well as more abrasive materials for brakes.

You have to be really careful to engage both front and back brakes at the same time though.