The Schengen area tends to be commonly misconstrued in the public perception as being 'border-free, defined by the unrestrained mobility of people,goods and capital. In reality the so-called 'internal borders' are still marked by a fervour of activities, conducted by the various national state agencies created for the purpose of territorial protection. Identity and migration checks - which often strikingly resemble pre-Schengen border checks - special crime-prevention tasks and transnational operations of police-type forces, detention and the unrelenting transfers of asylum-seekers and forced returns of illegalised migrants (also of EU nationals) are only a few among the many responsibilities of the various border-guard formations. This paper, based on data from fieldwork with the street-level Polish Border Guards working in the Intra-Schengen border region on the Polish-German border, analyses the impact of different levels of institutional discretion: official, local and individual, with a particular focus on the officers' behaviour and decision-making and on the role of discretion within the policy implementation of a specific procedure. Analysing the phenomenon of the forced returns (deportations) of EU nationals within the Schengen area, this paper exposes the nature of the little-known practice of cross-border transfers. It focuses on the phenomenon of a forced return of Polish citizens from Germany, specifically on the micro-level moment of transfer of custody between the German Federal Police (Bundespolizei) into the hands of the Polish Border Guards (StraZ Graniczna) on the Polish-German border, looking at the procedural variations and the decision-making of the officers, especially in the context of its street-level echelon and its practical contribution to the concept of deportability.