That is how this works ...

You would need to customize the file:
/includes/modules/order_total/ot_optionalinsurance.php

And change the setting from:
Code:
      if ($display_insurance && $insurance > 0) {
        $selection = array('id' => $this->code,
                           'module' => $this->title,
                           'redeem_instructions' => MODULE_ORDER_TOTAL_OPTIONALINSURANCE_TEXT_ENTER_CODE,
                           'fields' => array(array('field' => zen_draw_checkbox_field('opt_insurance', '1', $selected, 'id="opt_insurance"' . ($jsUpdateForm ? ' onclick="updateForm();"' : '')) . zen_draw_hidden_field('insurance', '1'),
                                                   'title' => $currencies->format($insurance, true, $order->info['currency'], $order->info['currency_value'])
        )));
      } else {
to read:
Code:
      if ($display_insurance && $insurance > 0) {
        $selection = array('id' => $this->code,
                           'module' => $this->title,
                           'redeem_instructions' => MODULE_ORDER_TOTAL_OPTIONALINSURANCE_TEXT_ENTER_CODE,
                           'fields' => array(array('field' => zen_draw_checkbox_field('opt_insurance', '1', true, 'id="opt_insurance"' . ($jsUpdateForm ? ' onclick="updateForm();"' : '')) . zen_draw_hidden_field('insurance', '1'),
                                                   'title' => $currencies->format($insurance, true, $order->info['currency'], $order->info['currency_value'])
        )));
      } else {