复选框组数组到字符串转换错误

I have a checkbox group array that is posting arrays, but not in my email. I'm using this code to 'implode' the arrays:

<?php
    if ( !empty($form->data['student']) && is_array($form->data['student'] ) ) {
      $session = array();
      foreach ( $form->data['student'] as $s ) {
      $session[] = "<tr><td>{$s['schoosedayM']}</td></tr><tr><td>{$s['sxcareM']}</td></tr>";
      }
    }
    $form->data['session_data'] = implode("
", $session);
    ?>

Does anyone know how I can get the checkbox group arrays to post in my email?