It sounds like they did the right thing after the baby fell. I used a high chair about 2 days before I decided it was an "accident" waiting to happen.
I've been in Restaurants, probably fifteen different times over the years and witnessed children falling out of high chairs (like the one's that McDonald's uses).
In fact, just about two weeks ago, at a Country Club in San Antonio, I saw a toddler take a "crash and burn" from that same type of high chair. Since small children are top heavy, they tend to go head first when they fall.
Well, I didn't mean to imply that every child that falls out of a high chair is a victim of bad parenting, but it is kind of a coincidence that Britney Spears was caught driving in her car with the baby in her lap (that was her, wasn't it?), and then she is getting in a new problem.