Has anyone implemented this with the Advanced Custom Fields plugin?
The following seems to work for core custom fields, but not with the plugin.
// Also obfuscate emails appearing in custom field values
add_filter( 'c2c_obfuscate_email_filters', 'change_c2c_obfuscate_email_filters' );
function change_c2c_obfuscate_email_filters( $filters ) {
$filters[] = 'the_meta';
return $filters;
}