As for people camping right next to you, I think it's because they believe you've scoped out the field and nabbed the best spot, so they should settle for the next best thing.
I've also noticed the same thing at empty picnic areas with scores of tables with me being the only one eating lunch; as soon as another family shows up with screaming kids, they will head toward me and sit at the closest table possible!
I'll bet the OP's camp is off the San Luis Rey River bike path near Oceanside...Hopefully the original photo doesn't have GPS data appended by the phone or camera.
Oh, wait, that photo's near PB..Tecelote canyon?
Last edited by stevepusser; 08-22-15 at 02:39 PM.