Removes the 'Members Only' title prefix from password-protected posts.

remove-title-prefix.php

<?php
/**
 * Removes the 'Members Only' prefix from password-protected posts
 * 
 * @see get_the_title()
 * 
 * @param string $protected Text prefixed to the title for password-protected posts.
 *
 * @return string The filtered prefix text.
 */
function wpdocs_remove_members_only_label( $label ) {
	// The %s specifier is replaced with
	// the post title after the filter is evaluated.
	return '%s';
}
add_filter( 'protected_title_format', 'wpdocs_remove_members_only_label' );