Don't show topics from subcategories

[cpradio]

This is related to

When in a category, default to "none" rather than "all" subcategories

I’d like to find a way to default the view for all users to display “none” rather than “all” subcategories, when in a category. “all” would be an option they could select. Is there any way to achieve this? Generally, my community is finding “none” as an option to select unintuitive.