Hi,
I have been both a hiker and a mtn biker. My feeling is you play it safe. I have seen hikers jump around apparently surprised; and that would not be good at speed. Actually saw a jogger hear a cyclist a couple weeks ago, and thought he would run across the road to miss her. Not smart, she was cooking
right along. I was nearly abreast of them, so any impact could have sent her flying at me. This weeks RBR newsletter has a page on hairpin turns. I found it worth reading, think you might enjoy it, too...
http://roadbikerider.com/manage-my-account.php