I would ask yourself if she is really getting spooked by something and trying to get away or if she just doesn't like being tied and pretends shes spooked so she can get away. If she is doing this every day, I would suspect the latter. I've had several horses come in whose owners thought/said they couldn't be tied.
Well, I would evaluate whether it was the first or 2nd reason why they're having so much trouble, but mainly found it was the fact that they didn't wish to be tied that was the problem, at least in the cases I saw.
If they were fearful, I would sack them out in the roundpen and that usually fixed it after a couple lessons. If they were being brats and just freaking for no reason (ie. hating being tied,) I would put them in a nice lil rope halter and go tie them to a stout tree. They eventually get over it in a couple sessions, depending on how stubborn they are. I've had some sit back and come forward into the tree, scratching their noses, but once they give it up, they'll stand there quietly. Might seem mean, but I'd rather them scratch their noses freaking out on the tree then hurting some kid at a playday or someones 40k trailer.
I would suspect since she does it so often, shes learned that she can get free if she sits back and will likely keep doing it. Figure out if she is legitimately doing it in fear or is trying to get free. Hope that helps a bit!