Standalone script for WordPress/BuddyPress to activate all users. Now, with debugging.

df_active_all_users.php

<?php

// Place in a file in the main folder (same as wp-load.php).
// Code is completely untested. Use at your own risk.

require( 'wp-load.php' );
df_activate_all_users();

function df_activate_all_users() {
	header( 'Content-type: text/plain' );
	$uids = get_users( array( 'fields' => 'ID' ) );
    	foreach( $uids as $user_id ) {
    		echo 'Updating UID '. $user_id . ': ';
		if ( get_user_meta( $user_id, 'wafp_is_affiliate', true ) ) {
			echo 'Hiding Affiliate';
			delete_user_meta( $user_id, 'last_activity' );
		} else {
			echo 'Setting active';
			update_user_meta( $user_id, 'last_activity', time() );
		}
		echo "\n";
    	}
}