Even if you are the German Chancellor, you still are, after all, a woman. And, as such, you are prone to this kind of patronizing fondling. Lindsay is dead right that "Every woman will recognize the guy who sidles up and starts "casually" giving you a backrub without even looking at you, because he wants to preserve deniability in case you freak out." While not exactly the same move, it reminds me of a scene from the old Spencer Tracy-Katharine Hepburn film, Adam's Rib, wherein Tracy gives Hepburn a backrub, which quickly turns aggressive.
She can recognize the "tone" of the touch immediately. I think a lot of women are attuned to the "tone" of touches. You can tell, for example, that when a man places his hand on the small of your back as you enter a room, it is often to guide you in the direction he wants, regardless of your own desire. I am sure others can think of some more fitting examples . . .