Which dangerous defects can have occurred on a trailer with overrun brakes which has been parked for some time?

Your answer is correct. When a trailer with overrun brakes has been parked for some time, the brakes may not work properly primarily because rust can build up on the brake components, reducing their effectiveness. Additionally, the cable connections that control the brakes can become defective or corroded over time, which can prevent the brakes from activating correctly. These two defects directly affect the braking function and are therefore considered dangerous. On the other hand, tire pressure does not typically increase greatly due to sun exposure; it might decrease or change slightly, but this is not a common cause of dangerous defects related to braking on trailers with overrun brakes. Understanding that brake function and cable integrity are critical helps ensure safe use of trailers after they have been stationary for a while.