United bumps child from seat, into mom’s lap for 3-hour flight

I totally agree that she should have spoken up. What happened to her and the child was totally wrong. However, in a circumstance like this, it's incumbent upon the mother to make her feelings known so the mistake is confronted. I'm sure that when she put that child in her lap that the crew was saying "Whew! Got away with that one." Then again, we don't know all the facts. She may have spoken up and been ordered to relinquish the seat... or she may have actually volunteered to relinquish the seat and only complained later. Either way, I think United is going to be throwing money at her to save PR!
I think you're right though, I would imagine that a small child in your lap would be a violation of FAA Regulations.

Back when I was a single father, something similar happened to me once, but it was an obnoxious passenger, and not the airline. I had bought my toddler son his own seat so that I could put his car-seat in its own seat and use the seatbelt to secure it, as one would do in a car. A rude passenger asked me to move the carseat because he wanted the seat. He assumed I had not bought the seat and was just hoping no one would want the center seat. I politely responded, "No, I bought this seat for my son" and produced the boarding pass. Luckily the guy realized his assumption and moved on.

Yeah, the mom should have stood her ground, especially for a $1000 ticket!