I voted "Critically Important" because that's why my mom and I started learning Aikido in the first place!
My brother has Down Syndrome and is very strong and occasionally he would get violent (which is unusual for Down Syndrome people) with my mom or I and we had to try to find some way to defend ourselves without hurting him. A friend pointed us to Aikido nearly 4 years ago and it has been a real blessing!
We have had to use it before and we were able to get him on the ground and control him until he calmed down and he wasn't hurt!
Someday, my brother will have to be placed in a special home. My mom and I have grown to love Aikido so that even after he's gone we plan to keep learning and having fun in our dojo.