Smart contract systems could change the nature of last-mile deliv- ery for the better through enhanced precision, coordination and accountability. However, technological complexity poses a chal- lenge for end-users participating in the design process, making it hard to explore their experiences and incorporate their perspectives. We describe a case study where technological prototypes create smart contract experiences for professional couriers and receptionists, allowing them to speculate about emerging possibilities, whilst remaining grounded in their current practices. Participants enacted a series of deliveries, choreographed by smart contracts, and their responses were explored in post-experience, one-to-one interviews. Working with professionals to explore the potential impact of smart contract technologies, revealed the systemic webs of value underlying their existing work practices. This has implications for design of such technologies, in which increased automation, efciency and accountability must be delicately balanced with the benefts of sustaining personal values, relationships and agency.

This paper presents GeoPact, an assembly of technological objects that materialises location-aware smart contracts using internet of things and digital ledger technologies. Such contracts may facilitate the creation of distributed systems and services for transport and logistics that are locally constructed and adaptable, thus supporting specific community needs and sustainable objectives. However the technological infrastructures that underpin these systems are complex, making it difficult to engage publics in design processes. GeoPact grounds infrastructure in relatable physical activities, that are linked with holistic views of the system, and creates new experiences for public engagement. In these activities participants were invited to roleplay as couriers, and to progress through delivery scenarios which were governed by smart contracts. Participants and spectators were then encouraged to discuss their reactions, concerns and ideas. This paper illustrates the GeoPact assembly and reflects on our engagement activities.