This paper presents selected findings from a recent empirical research conducted in the context of modernization of public administrations. E-government adoption has reached a stagnation point over the last few years in the DACH region. The European Commission has been working intensively on projects aiming to overcome the existing digital barriers between EU Member States. Citizens repeatedly provide the same personal information to different public authorities, which causes frustration and inefficiency. The Once-Only Principle suggests that citizens should have the right of providing information to public authorities only once and that the provided data will be exchanged between national authorities of the EU Member States. By signing the Tallinn Declaration in October 2017, EU Member States have already committed to implement this principle. Sharing personal data of individuals between public authorities within national boundaries as well as with the public administrations of other EU Member States would assuredly ease-up data provision and increase efficiency. Yet, higher convenience comes at a cost of data protection and privacy, which becomes highly critical when sensitive personal data is involved. From this standpoint, a particular emphasis needs to be placed on understanding expectations, sensitivities and privacy related concerns of citizens, which is argued to be one of the key drivers behind the adoption of G2C e-government initiatives.