I had relatively the same thing happen to my car in December 2010, except the driver that hit it came into the restaurant and informed me. He'd backed out of his space, didn't see my car because it was in his blind spot, and only bumped my car lightly at very low speed. (I've known the guy most of my life, and know that he's a careful driver.)
The plastic bumper cover flexed under the force, and did so enough to bend and break some metal brackets and the housing for the headlight. There were 2 very minor scratches on paint on the top corner if the bumper cover where his car contacted mine, which I would not have noticed anytime soon. As a result of the bent and broken brackets and housing, the headlight assembly pop out if place slightly, and was aimed down about 10-20 degrees from normal.
If he wouldn't have told me about the incident, I wouldn't have noticed it until I drove at night with the headlights on.....and the one now aiming quite low!
Repair bill was $486, which was paid in full by the other guy's insurance with no questions or arguments.....thankfully.
They sure don't make cars like the old 60's Ford battleship that I used to own. I plowed into the back of a Dodge Dart, that ended up about 3 feet shorter. The rearend of the Dart put a small scratch on my car hood, and a little bit of green paint transfer onto my big chrome bumper.