It would be very good to check if a plugin is digitally signed and disable requesting for verification if the plugin is
not signed. This would save time for both plugin owners and plugin verifiers. If the plugin is not signed then "Submit"
button should be grayed out and red warning "The plugin is not signed. How to sign a plugin?" should be displayed
somewhere near where the "How to sign a plugin?" text should be a link to FAQ entry describing what to do in such case.