Allow metabox dragging, but disable saving the new order on the server side.
<?php
function ccd_prevent_meta_box_order( $action ) {
if ( 'meta-box-order' == $action /* && $wp_user == 'santa claus' */) {
die( '-1' );
}
}
add_action( 'check_ajax_referer', 'ccd_prevent_meta_box_order' );
?>
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