"Secure area..."

...that's what the platforms at Waverly train station are, according to the security fella that quizzed me tonight when I was taking this blip.

It was all perfectly civil, and after seeing the shots I'd taken he was happy and wandered off, but it did leave me wondering where the line between public space and "secure areas" could/should/are/aren't drawn. A big topic for photographers I know, but first encounter for me!