Some things work in therapy and some don't. I don't think the therapist will try that particular route again and I don't see that it "hurt" anything to try it. My T tried a couple of times to help me learn to breathe with her (but not sitting with me at the time) and that was too much for me, I was too anxious/scared and my defenses at the time didn't allow me to participate. I don't think either the therapist or your girlfriend could know how it would play out until it was tried, a backrub is hardly molestation but could be, if a person is not ready or doesn't benefit from it, be seen as an invasion of space/boundaries which your girlfriend's therapist recognized and apologized for. If your girlfriend likes her therapist I would continue to see her, work with her and be glad she's trying lots of different things. If your girlfriend has always been afraid of and anxious with her therapist, doesn't "like" her and the things she tries, I'd find another therapist. But it's up to your girlfriend, what she thinks, feels, experiences, etc. Nobody outside the relationship can "judge" other than if it were to continue when your girlfriend said "no" and/or exhibited discomfort behavior (if the T had not been bright enough to pick up on it, was doing her own thing at the expense of the client) or if there were other sexual or boundary intrusions after this.