Emerging wearable robotics demand design approaches that address not only function, but also social meaning. In response, we present Sumbrella, a soft robotic garment developed as a speculative fashion probe. We first detail the design and fabrication of the Sumbrella, including sequenced origami-inspired bistable units, fabric pneumatic actuation chambers, cable driven shape morphing mechanisms, computer vision components, and an integrated wearable system comprising a hat and bolero jacket housing power and control electronics. Through a focus group with twelve creative technologists, we then used Sumbrella as a technological probe to explore how people interpreted, interacted, and imagined future relationships with soft robotic wearables. While Sumbrella allowed our participants to engage in rich discussion around speculative futures and expressive potential, it also surfaced concerns about exploitation, surveillance, and the personal risks and societal ethics of embedding biosensing technologies in public life. We contribute to the Human-Robot Interaction (HRI) field key considerations and recommendations for designing soft robotic garments, including the potential for kinesic communication, the impact of such technologies on social dynamics, and the importance of ethical guidelines. Finally, we provide a reflection on our application of speculative design; proposing that it allows HRI researchers to not only consider functionality, but also how wearable robots influence definitions of what is considered acceptable or desirable in public settings.