The lifts rising to Yitu Technology's headquarters have no buttons. The pass cards of the staff and visitors stepping into the elevators that service floors 23 and 25 of a newly built sky scraper in Shanghai's Hongqiao business district are read automatically – no swipe required – and each passenger is deposited at their specified floor. The only way to beat the system and alight at a different floor is to wait for someone who does have access and jump out alongside them. Or, if this were a sci-fi thriller, you'd set off the fire alarms and take the stairs while everyone else was evacuating. But even in that scenario you'd be caught: Yitu's cameras record everyone coming into the building and tracks them inside.