photographers like to set up in cool spots, tops of hills, etc, alot of times you just come up on them, naturrally after miles of trails, suddenly a wierd looking beast is on side of trail, horses head is going to pop up and look.
Im also going to bet most endurance riders arnt grinning and waving for 50 miles.
The thing that gets me though is quite a few AERC members on various forums have complete melt downs over a picture of a rider without a helmet, yet at a recent ride in Georgia, with a 3-6 foot deep or so river crossing I saw lots and lots of pictures of horses with tiedowns and martingals. That is just insane. People needed to be jackslapped. Surprisingly no uproar over it.