I'm trying to picture this..but I'm afraid I just can't. I do know my husband was pretty tough on his, and it was really hard to tip, although they do tip. I would think roll bars would just make a cage..not keep it from tipping..but I would test it.
Gotcha..yes...the chair can tip sideways. I have seen it happen. It takes an odd movement, and some force, but it can. My husband, like I said, used to end up in all sorts of very strange positions in a pile of body and chair..on the floor. (although he thought it was humorous)
And, she should have handled it better with you instead of yelling. Especially if you didn't know.