Revised version of kill PDFs (WT 1.0.1)

function removeWooTicketsPDFs() {
    $pdfCallback = array(TribeWooTickets::get_instance(), 'add_PDF_to_email');
    remove_filter('woocommerce_email_attachments', $pdfCallback, 10);
}

add_action('woocommerce_email_attachments', 'removeWooTicketsPDFs', 5);