She was clearly guilty but there was also no actual harm done (the baby was returned the same day) and the woman had her reasons that she felt she was protecting the child from abuse.

I feel like I've seen this same sort of story written by the same people and the same actors multiple times (maybe I just watched too many seasons of Switched at Birth). It's heartbreaking though and I'm sure common. Parents of deaf kids who don't bother to learn sign language.