I've read quite a few of these responses and, frankly, I'm surprised by a lot of them.

First things first: I'm sorry your son was injured, and I hope he's fine and not put off of flying.

With that said, nothing I've read indicates that the woman who dropped the bag committed a criminal act. Call the police? Call her a "perp"? Please! It would have been courteous for her to stay, and I'd think she'd care whether she accidently hurt someone, but I'm not aware of ANY law, civil or criminal, that required her to remain (and I am a lawyer -- and, no, this isn't legal advice, no one here is my client, for legal advice retain a lawyer, etc.).

It's also not clear from the description of the incident how it came about that the second bag fell out out of the bin when she removed her own. In a civil law context, the woman might have incurred liability for negligence IF her actions in removing her bag fell below the standard of care that would have been exercised by a reasonably prudent person. I don't know whether they did or did not -- it's certainly not clear from the description.

And, at the risk of incurring some flames, let me also suggest this: an airplane cabin, particularly during boarding and deplaning, is a crowded, chaotic place. We adults recognize that there are heavy things in the overhead bins, and our general awareness and peripheral vision is usually enough to protect us from these kinds of accidents. Children don't share this awareness, and don't recognize an airplane cabin as the potentially dangerous place that it is. I don't think it is appropriate to expect other passengers to watch out for children that are not in their own custody -- that's the job of their parents/guardians. I'm not suggesting in any way that the OP was responsible for the little boy's injuries -- obviously, she was not. However, I don't think all the blame should be placed on the woman who removed her bag from the overhead.