When I hiked Miller Peak, the road to the trailhead was being patrolled multiple times per day by the border patrol. Apparently the mountain is a favorite hide-out for illegal immigrants sneaking across the Mexican border, just 5 miles away. I was told to keep my group together and for our own safety make plenty of noise as we hiked. Along the summit ridge there was plenty of evidence of constant activity, and the otherwise beautiful trail was strewn with discarded food containers and torn up clothing. Unless the mountains are cleaned up of this sort of presence, Miller Peak is probably not the sort of trail one would want to hike alone or during non-daylight hours.