The solid tree, page-25

Love your research Tony, I wonder however how e-surveillance can be compared to a security guard.
(Don't know why my puter is typing in bold now)
A security guard protects customers and the machine from threat, which after living in South Africa I can tell you I would rather a guard protecting me then a camera recording the incident.
Obviously if there is not much threat or danger then e-surveillance may be enough but the fact that they are using a guard suggests to me that they must need some protection.