Actually, what she did was proper and correct. Called out to you in a clear tone that she was approaching on your lefthand side. In this case, YOU didnt know the rules.
I love the "no hikers" trails were I am! But...guess what....those damned arrogant smug runners and hikers and dog walkers (no dogs allowed, either) still muck up the joint. But I usually just slow down, let them pass, tell them my riding intentions, say hello and warn them they are on a bikers only path and to be careful. And then I go on my way. What I DONT do is get my clams steamed and then run home and whine about it online. Im funny like that.
Wait....you want us off the roads...so we say "OK" and go into the woods....then YOU follow us there and its OUR fault when you get all tangled up in our business? It sounds like they didnt see you around a blind corner, just like you didnt see them. So you both got startled a bit and went on your way. Problem?