They’d reached threshold. The level of discount the systems had set were right… of course. Enough people had agreed: the data was flowing. Those who’d refused were just anonymised footfall points on the smart walkways, their pace and pause stats adding to the real data from the band wearers. The screens in the control room gave snapshot views for brand partners but the real data was being crunched as part of the auctions. Facial recognition emotional fall-off; biometric arousal points; vocal interest signals all cross referenced with the visitors’ feeds and history. The billboards responded as the brand partner smiled.