Uhm... Early Childhood Educators do give F's in walking and block stacking and a variety of gross motor, fine motor, cognitive skills. They might not call it that to the parents, but that is exactly what it is. They do screenings like the Denver, LAP, and eLAP that tell where a child is in development and point to exercises to do or the very real need to get specialized help for the infant / toddler. Failure to get help could cost us taxpayers big bucks (1M+) over the course of the kids life.
So, yes, your child can flunk walking or block stacking.
It's true. I failed something called "Running, Skipping, and Jumping," when I was in kindergarten. I was a clumsy child, and I also had difficulty understanding what the gym teacher was barking at me. My parents found it hilarious.
I can do all three of those things just fine now, by the way.
So, yes, your child can flunk walking or block stacking.