Rear-ended but no damage

Sitting at a red light when a woman apparently takes her foot off the gas and pops me in the rear. As I'm getting out I'm thinking "Oh no you've got to be kidding me." She's immediately giving me her "I've had such a rotten day" excuse as I'm walking back to the rear of the car. I say "Do you have any idea what you just ran into?" She says "Yes I know a baby when I see one." I look her over real good (the car although she wasn't too shabby either) and no damage so I guess those 5 mph bumpers do their job. I wasn't too happy about it though.