mypmpro-remove-sm-pbc.php

<?php //do not copy

/**
 * This recipe will remove the confirmation messages from Sponsored Members on checkout and email
 * when a member pays by check. Only once payment has been received will the codes show.
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function mypmpro_sm_remove_confirmation_messages(){

	$morder = new MemberOrder();
	$morder->getLastMemberOrder( null, '' );

	if( $morder->status == 'pending' && $morder->gateway == 'check' ) {
		remove_filter( 'pmpro_confirmation_message', 'pmprosm_pmpro_confirmation_message' );
		remove_filter( "pmpro_email_body", "pmprosm_pmpro_email_body", 10, 2 );	
	}

}
add_action( 'init', 'mypmpro_sm_remove_confirmation_messages' );

This did not seem to work on the init hook, but changing that to pmpro_after_checkout worked as expected