Had that very thing happen to us last year. We busted a group of elk from their beds in the afternoon. I saw one butt heading out through the trees, but from the sound of them, there was quite a few of them.
My brother and I hunkered down and he let out a few cow calls. Next thing I know, elk are meandering all over the place and beginning to feed. After about 5 minutes of watching elk sprinkle out all over the place, none with antlers might I add, the lead cow let out a bark that echoed throughout the canyon, and almost caused me to shat myself. I have never heard that before, and couldn't believe how loud she was...felt like she was right on top of us. We watched them, and listened to her for about 30 mins.
Anyway, yeah, it does work. I never thought it would, but I will be carrying a call with me come next week in case I am in the same situation. I think as long as they don't wind you, you still have a shot. If they get your scent, it's all over with.