Left-hook, Right-hook

This morning an incident happened that I think is an indication that motorists in Chattanooga are trying to become more considerate but sometimes just totally don't get it.
I was coming down McCallie Avenue as usual, riding in the bike safe and legally allowed place of about 4 feet from the curb. As I was on a slight down hill, I was moving at a pretty good clip. But it wasn't fast enough for the driver of the white minivan behind me, who impatiently left hooked into the other lane to gun past me. Nothing unusual in that. There are always the drivers that act insulted that they have to make an adjustment for bicycles.
But this driver did a sudden right hook back into the lane for a right turn. Again this happens sometimes. This maneuver is dreaded by all cyclists and is probably the number one cause of bicycle/car accidents. Its the reason the Quick Right Turn defense move is taught in cycling safety classes. And the reason for bike placement of away from the curb.
But the driver suddenly turned polite and considerate to me. She slams on the brakes to stop in the middle of her right hook and then patiently waits for me to go by,blocking traffic in both lanes. Of course, by this time I was very wary of her. She had me trapped into forcing me to pass her on the right side, setting myself up to be creamed if she decided to change her mind. Not a very comforting situation! So I slowed down to allow response time to any more moves on her part as I passed her in the narrow passage she allowed me.
As I passed her, I wagged my finger at her to let her know that what she did was a no-no, Noticed I said I wagged my finger at her, I didn't give her the finger. I try to always be civil in my dealings with drivers. And I have to say she was being quite civil in her rudeness to me.
Which probably made my admonishment confusing. She probably thought I was telling her it was wrong to politely wait on me. I hope she was aware enough to know the left-hook, right-hook maneuver was the one I was telling her no to. What do you think?