To remove the second sidebar permanently using the Genesis frameworks:
In your child theme’s functions.php file add this to the bottom:
genesis_unregister_layout( ‘content-sidebar-sidebar’ );
genesis_unregister_layout( ‘sidebar-sidebar-content’ );
genesis_unregister_layout( ‘sidebar-content-sidebar’ );
This will remove that extra side on all pages on your entire WordPress website, including the options on the individual pages and posts, making it less confusing for the client.