I've encountered mountain lions many dozens of times (?50- 80 times). Every time I was only aware of they were there because one of my dogs alerted me to their presence. She was the ultimate guard dog. She only twice had to charge a lion. But unlike when she chased off black bears and treed them she knew the scaredy cat was spooked and wouldn't pursue. Humans are generally oblivious when mountain lions are watching them go by. Mountain lions are solitary hunters. They are genetically very risk adverse as injury may result in starving to death. Sure, it was reassuring to have a dog alert and if necessary charge a mountain lion but realistically, lightening is a far bigger risk on the trail as is just the drive to and from places to enjoy the outdoors.