Nope cat permissions will surpress it
Looking at the way things are done does this not show what the parent cat is?
Wildlife and Flowers Galleries->Bears
If it is in the cat list then they can upload to it so placing categories in a list to upload to without having them selectable in a select box can not happen. Thats the very purpose of select box. We grab the cats that people have permission to upload to and format every row as an option in a select box with a value of that cat being passed.