Even if you are completely right about everything being as simple as you say, nobody wakes up and says “gee, I’m going to be stupid/self-destructive/neurodivergent today and cause myself a lot of pain.”
The answer is to use it as a case study to improve the design or perhaps provide a leaflet, QR code to a PDF, or a laminated card to assist renters with controls that are safety critical or unique to the vehicle