What is the key reason to park a trailer on level ground?

Parking a trailer on level ground is primarily important for maintaining stability and safety. When a trailer is parked on an incline, it can shift or slide, creating a dangerous condition that could lead to accidents or damage. A level surface ensures that the weight distribution is even, which helps keep the trailer securely in place.

In terms of safety, a stable parking position minimizes the risk of the trailer rolling or shifting unexpectedly. This is crucial for both personal safety and the protection of the trailer's contents, as well as other nearby vehicles and pedestrians.

While other factors like ease of loading, brake wear, and theft prevention are considerations, they do not prioritize the fundamental need for stability and safety when parking a trailer, which is essential for preventing potential dangers.