Is it ok to let a 3rd grader walk home from school alone?

My husband picks the kids up from school because he gets off work before I do. We have a 3rd grader and one in Kindergarten and they go to different schools. He has been picking up 3rd grade first and then dropping her off at the other school and letting them walk home, which is 3 blocks. The weather has been nice and 3rd grade asks to walk, so he thinks it’s ok.

We live in a small town of about 39,000 in Kansas. I know I am over protective but people are nuts anymore, so I think you have to be so careful.