I was walking around Camborne for the collectables when I noticed that there was an 'E - Climb Up' option onto the flowerbeds on platform 2. Presuming my virtual self would not destroy the flowers (!) I climbed up, only to find that I couldn't return back down to the platform. But I could exit into the car park, whereupon I discovered that I was on the other side of the invisible wall and could wander around the surrounding roads freely. Couldn't get back into the station without exiting to Main Menu, but was able to replicate this at will. Unintended back door or Easter Egg?!
I think it's intentional, at Lake(?) on the Isle of Wight there is a similar thing - both being Rivet products, I imagine it's no coincidence.
Yes, I've just tried that. You can jump onto the ice cream freezer and then over the back fence and into the village.