The ferry operators plying the Rhine are nothing if not direct.
Turn off your engine!
Pull on the handbrake!
Switch off your lights!
Stay with your car!
All passengers are required to obtain a ticket before commencement of the journey (what was that about not paying the ferryman until the other side..?), to retain it and show it on demand.
Passengers not holding a ticket will be forced to walk the plank.
I think that’s what it says, anyway…