Hide widgets by sidebar ID on members only content when the current user does not have access.

my_pmpro_widget_display_callback.php

<?php
/*
  Update line 8 with the array of sidebar IDs you want to filter.
  
  Add this code to your active theme's functions.php or a custom plugin.
*/
function my_pmpro_widget_display_callback($instance, $widget, $args) {
	$hide_sidebars_array = array('sidebar-1','sidebar-2');
	global $post;
	//check if current user has an active membership level and hide the sidebars.
	if( pmpro_hasMembershipLevel() ) {	
		if(in_array($args['id'], $hide_sidebars_array) )
			return false;
		else
			return $instance;
	}
}
add_filter('widget_display_callback','my_pmpro_widget_display_callback', 10, 3);