The applicability of exoskeletons in different daily and occupational settings is continually increasing. Due to varying tasks and user groups, the adaptability of exoskeletons is becoming more significant, with increasing demands for smarter devices. The implementation of force sensors in exoskeletal interfaces could be an approach for analyzing the human-machine interaction in terms of, e.g., wearing comfort, support, and motion synchronicity, as well as optimizing this interaction in real time based on the analyzed sensory data. For this, force sensors need to be embedded in interfaces, which implies the consideration of inexpensive sensors to minimize the total purchase price. However, measuring contact forces on the wearer is challenging and inexpensive flexible force sensing resistors have limited accuracy, repeatability, and stability. This paper evaluates the suitability of an interface principle working with two water capsules and two embedded piezo-resistive pressure sensors in different test scenarios derived from real exoskeletal application examples. Finally, a comparison of the capsules' inner pressures reliably detects different load conditions on the interface such as centered, edged, and shear forces. Thus, this principle seems to be suitable for further exoskeletal considerations.