Even in a seemingly borderless world, differences do not disappear. To cross a border needs more than just getting rid of the physical and institutional barriers at the border. It requires that one is interested in what is offered or what is to be found at the other side of the border, or that there is a real need for that what is available at the other side of the border. Especially in cases where borders have a long tradition, people often seem to have accommodated themselves in these situations, and have no intrinsic needs or interests in exploring the opportunities at the other side of the border, when borders get easier to cross. This dis-interest is sometimes also denoted as a threshold of indifference. Only when this threshold is surpassed cross-border interaction will substantially increase. Of course this subjective threshold can differ from person to person. The one’s with a low threshold will probably also be among the cross-border pioneers, when barriers at the border are torn down. Through their presence and through their cross-border interactions, also for others, as an unintended consequence, the situation slowly but surely changes, and they become more familiar with the border and the cross-border opportunities, and at a certain moment they also surpass that threshold of indifference.
Dr. Bianca Szytniewski, successfully defended her PhD-thesis on Dec. 7, 2018, on exactly this topic, focusing on cross-border shopping behaviour.
On the back cover of her book it says: ‘Borderlands can be perceived as sites for encounters with both differences and similarities. When crossing a state border, we move from one state to another, come across different people and cultures, hear different languages, notice different characteristics of our surroundings and submerge in otherness. At the same time we might find out that locals in restaurants or shops speak our language or sell known brands and goods. Our border experiences, local narratives and regional histories colour our perceptions of a borderland and enable us to give meaning to the differences and similarities we encounter. Some of these may be known and expected, but many others can be new and unfamiliar. 
According to various scholars not only familiarity but also unfamiliarity can encourage cross-border practices. Unfamiliarity resulting from differences in, for instance, culture, landscape or facilities between the two sides of a state border can trigger interest and curiosity, and consequently lead to cross-border mobility. This dissertation further unravels this notion of familiarity and unfamiliarity in relation to encounters with differences and similarities in European borderlands, by offering theoretical reflections on familiarity and unfamiliarity, and examining cross-border mobility, shopping practices in particular, in the Dutch-German, German-Polish and Polish-Ukrainian borderland.’ If you are interested in reading more, click here.