At the Zaanse Schans you borrow a trailer with a permitted maximum mass of 1,300 kg. The owner has fitted both an auxiliary coupling and a breakaway braking device: 'double is doubly safe'. What do you do?
You drive off as it is; below 1,500 kg both may be fitted together
You have one of the two removed; together they may not be fitted
You drive off as it is; two devices give extra security if it breaks loose
Explanation
False — you think two devices give extra safety. A trailer with a breakaway braking device may not also have an auxiliary coupling: the two work against each other (Book p.231).