In the queue for the ferry to Terschelling you hitch a wide caravan. Through the normal outside mirrors you mostly see the caravan and hardly the traffic behind you. It is 07:50 and the boat leaves soon. May you drive on board like this?
Yes, extra outside mirrors are advice here, not a duty
Yes, through the inside mirror you see the traffic behind you well enough
No, first fit extra outside mirrors that look past the caravan
Explanation
False — you rely on the inside mirror. With a caravan behind, the inside mirror looks straight at the caravan; if the caravan blocks your view through the normal outside mirrors, you must fit extra outside mirrors (Book p.230).