BuddyPress.org

This is how I did it on my site: (it just prevents BP from registering the widgets)

// Remove buddypress widgets from blogs other than the main blog
function hide_bp_widgets() {
if (!is_main_blog()) remove_all_actions(‘bp_register_widgets’);
}
add_action(‘plugins_loaded’, ‘hide_bp_widgets’, 1); // Has to run before bp_setup_widgets()