Lots of crime up there that the Plod needs to keep an eye on???
Local lowlifes from the city, go up on the hills, cruise the parking areas, and break into peoples cars whilst the owners are out walking. Easy pickings. Especialy on busy weekends when the weather is nice, there will be hundreds of parked cars around. Even if the owners saw them, they would probably be too far away to do anything about it.
Its a popular crime "up north"
Hence the patrols...!