Building information modeling (BIM) involves the use of collaborative digital mock-ups of an asset to streamline design, building, and operation processes. Collaborative work and the use of an integrated digital mock-up offers many advantages but raises several problems regarding the liability of stakeholders in construction projects. Practitioners involved in the design process of a building (engineers and architects) practice very high-liability professions for which the use of a digital mock-up implies potentially high stakes. Although liability issues have been identified in the literature as a hindrance to BIM implementation, practitioners’ concerns toward their liability have only barely been investigated. In this paper, we propose to explore engineers’ concerns about their liability toward using BIM collaborative digital mock-ups with a case study in civil engineering. We documented these concerns through an exploratory study consisting of semi-structured interviews. The main contribution of the paper is therefore an organized list of concerns. These include: the alignment between their way of working and professional rules, the clarity of the assignment of liabilities, and the reliability of the digital mock-up. These stem from a liability risk that practitioners perceive because of uncertainty about liability allocation and uncertainty regarding the reliability of digital mock-ups. Our research work is part of an overall effort to understand the problems faced by practitioners when implementing new practices associated with BIM and to provide solutions. The results are therefore extensively discussed in order to identify hypotheses and avenues of work to address the identified concerns. The specific context (engineers, in Quebec) and the exploratory nature of the study implies that the results are not generalizable to a wider population. However, the identified concerns may be likely to emerge in similar context like high-liability professions involved in design stages of BIM projects. This paper is a very first step toward identifying these concerns in the construction sector and must be subject to future work.