Hostile architecture: an uncomfortable urban art – in pictures

"Julius-Christian Schreiner’s Silent Agents series, shot in London, Paris, Innsbruck and Hamburg, depicts examples of ‘hostile architecture’: subtle interventions in urban spaces designed to hinder people’s use of them."

I found this series of images quite disturbing. It made me think of the people who design these 'interventions'. Are they proud of their work, or do they have trouble sleeping at night?