I do kinda disagree with them using such measures on a child. Surely they could have just picked her up and carried her to the police station? She can't be that heavy, and the officers must have had some strength in them.
On the other hand, handcuffs and leg restraints aren't going to scar her for life, unless the officers didn't put them on properly. They're not really that bad, so I don't think her mum should be making quite so much drama about it. The anti-spit hood might be a bit much, because having your face covered is pretty much always the most degrading way to be detained, but hopefully the officers weren't too aggressive about forcing it on her.
I think it's stupid that everyone's focusing so much on the fact that her mum thinks she's 'disabled' though. She hasn't even been officialy diagnosed apparently, and her mum actually only thinks she has autism. Autism is not a serious disability(compared to something like Down's Syndrome), so I don't think it should factor into this case at all. As far as I'm concerned, the only factor that needs to be taken into consideration here is the fact that she was a child, and might not have been completely sure what she actually did wrong.(all kids have that problem, not just 'autistic' kids)