Your second story reminds me of a time we were set up for a nice like near Smedberg Lake in Yosemite---about 25 miles from the nearest trailhead.

A group of horseback riders had arrived at the lake, and as watched they dismounted, and started setting up for their own lunch. One woman walked along the lake until she was right in front the trees that were shading and us and started to undo her pants.

I cleared my throat, and she jumped, spotted us, and quickly walked the other way.

I should have done what you did, and told her to go farther from the lake...but she may not have needed to go at all anymore, after that little scare.