The answer to this question (regarding the choice of preposition for specifying a location) suggests that the preposition an would indicate the outside of an object, whereas the preposition in indicates the inside of an object. In that particular question, the object being discussed (a computer) is small and has an obvious inside and outside to the box.
Does the same conclusion (inside vs. outside) apply to the following two sentences that appear in the Goethe Institut vocabulary list for Niveau A1?
- Die Fahrkarte bekommst du am Bahnhof.
- Blumen kannst du in jedem Bahnhof kaufen.
Should I understand that tickets are to be purchased somewhere outside the station building but flowers are to be purchased inside the building? Or is there some other reason (perhaps stylistic) for the choice of preposition?