Quote Originally Posted by spokewench
Just this morning, I was riding to work - I was in a hurry so I was movin right along but this incident happened on a slight uphill so I wasn't goin that fast! This fit looking girl with long blond hair is walking up the hill on the FUTS trail near the community college. As I come up on her a little ways behind her, I say "On your left" in a pleasant but to be heard voice. She looks over her shoulder to her left looks right at me and jumps as fast as she can into the left hand side of the trail!

I shook my head and thought maybe she really is a true blond! (Sorry for the blond joke, but I couldn't resist thinking it).
I am not hard of hearing, but lots of times when people come up behind me and shout out something, I will only hear the last part of what they said. This girl sounds like she heard you say "(mumble mumble)..LEFT!"
I am sure this is what happens a LOT when we come up behind people to pass them. I have a classic sounding bike bell (brring-brring!!) and I use it well ahead of when I'm coming up behind people either walking or on bikes. Because it's a classic bike sound, they instantly know there is a bike coming, they look back and step out of the way in a logical direction. No confusion, and I'm not seeming to give them weird instructions on what direction to move to.