.... and may choose to only fit one on cost and security grounds - the atmospheric retention system employed by the docking tube may not be cheap and one at each end would encourage drive-through attacks....
Security didnt seem too tight to prevent people launching attacks from WITHIN the station now did it? So thats yer 'security' one debunked. Ner. As for cost, well are you implying that these stations were subject to a value engineering exercise? It would at least explain the rubbish PA system.
I employ Structural Engineers to wash my car. Some architects DO actually know some physics you know!
Just kidding about the car though, some of my best friends are engineers.
SE only have to wash cars due to late and overdue invoices that architects fail to pay on time. 'Some Physics' is appropriate, its just the physics they do know bares no resemblance to the physics they need to know in order to build things. Its rare to find an old school architect who knows that Youngs Modulus isnt a face moisturising cream.
Grandad was an architect, but he was the black sheep of this engineering dynasty or dysentery as it is at the mo due to a dodgy kebab.