I know how you feel. My ex moved when we were sharing custody and refused to tell me until 3 months later. He also refused to offer me first right of refusal ALL the time. He'd rather have his parents watch the kids then let me pick them up. But hey, thats what people who think they are above the rules do.
Do you think its possible she didn't know she had to inform the courts? I mean, ten minutes away isn't akin to moving to another town (Or it could be I suppose, depending on where you live). Perhaps she thought it uneeded? Thats giving her the benefit of the doubt.
As the the accused child abuse, unless you have marks, or its coming out the child's mouth, the system is rather slow. My two best friends work for the child protection services, and they pretty much have their hands tied unless one of those two factors are in place.
What does the child say?
-------------------- I can't live within you-- David Bowie