Typically a mountain lion sighting would not be any kind of news but it's the location of the mountain lion that's so interesting! In Orange County, mountain lions roam the Santa Ana Mountain Range and the adjacent canyons/hills. Due to the heavy development of Orange County beginning in the second half of the 1900's, the mountains lions of Orange County have really been sealed off exclusively to the Santa Ana's. Same goes for the other side of the mountain range with Corona being heavily developed in recent times.
Once in a while a mountain lion will stray away from their "known" range in the mountains and show up on someones security camera in a residential or business area. It's typically younger males that have recently left their mothers side and are trying to find new territory. These cats don't understand our ways of life and the dangers that human civilization pose to them. These sightings sometimes tend to be in places where people don't expect mountain lions to be, making it a surprise. Previously, there has not been a mountain lion sighting documented on the coastal side of the 5/405 freeways in Orange County in at least the last 30 years or more since OC has been so developed. While mountain lions of course used to roam all the way to the coast, it would simply be very difficult for them to get there, crossing freeways, streets, and roaming through residential neighborhoods.