You're right. She is 'bomb-proof to a fault' in that you can't get her out of your way either. All I have to do is cluck at Bay and he moves out of the way. She'll stand there with me slapping her and not 'move it'.
She was bottle fed, as her mother had to be put down after the birth, so she is perhaps "too imprinted" ;~D
Oh yeah, I forgot about her being a bottle baby. Those are usually really spoiled coz they don't seem to realize that people aren't just like horses. You've really got to "turn up the volume" with them to get them to react. You'll have to put on your "nasty tempered boss mare" act with her. I know this sounds weird, but with Bob, I have to bring up this mental image of me getting really big and mean, like a grizzly bear. I don't know how it works, but maybe by me calling up that mental image, I'm unconsciously changing my body language accordingly. Whatever it it, it works. LOL!