Abstract: This paper discusses how the public setting of a situated display acts as a resource for security. The very publicness creates a social auditability that prevents certain kinds of abuse. This is illustrated through our experience with Hermes - a situated door display that allows electronic notes to be left. Potential 'security' threats have not materialised due, we believe, to the physical setting of the devices. There are an increasing number of situated displays "in the wild" and these need both control but also freedom of access. The use of space may be powerful means to enable this in suitable circumstances.