It is an implicit assumption in the field of brain-computer interfacing (BCI) that BCIs can be satisfactorily used to access augmentative and alternative communication (AAC) methods by people with severe physical disabilities. A one-day workshop and focus group interview was held to investigate this assumption. Rehabilitation professionals (N = 28) were asked to critically assess current BCI technology, recommend design requirements and identify target users. The individual answers were analyzed using the theoretical framework of grounded theory. None of the participants expressed a perception of added value of current BCIs over existing alternatives. A major criticism (and requirement) was that the usability of BCI systems should significantly improve. Target users are only those who can hardly or not at all use alternative access technologies. However, such persons often have concurrent physical, sensory, and cognitive problems, which could complicate BCI use. If successful BCI use continues to require a user to sit motionlessly and have intact cognition, then -as previously implicitly assumed -people in the locked-in state (resulting from late-stage amyotrophic lateral sclerosis, multiple sclerosis, spinal muscular atrophy type II or classic or total locked-in syndrome) and people with high spinal cord injury (C1/C2) could be target users.