Thinking about devices/services that can be used for multiple purposes.
How important is it to label these devices to communicate their function in a specific usage scenario? What kinds of products or devices are labeled in your culture? When does labeling products (from a design perspective) implicitly admit that there is no appropriate affordance or forcing-function present? Think about door handles with push/pull labels. What can we learn from street hacks for the design of affordances in product and service design?