gistfile1.php

	public function customDBMS($context)
	{
		$fieldName = 'changeMe'; // change this to your checkbox field name
		
		$event = $context['event'];
		$section = $event->getSource();
		
		require_once(TOOLKIT . '/class.sectionmanager.php');
		if (!$this->sectionManager)
			$this->sectionManager = new SectionManager($context['parent']);
		
		$section = $this->sectionManager->fetch($section);
		$schema = $section->fetchFieldsSchema();
		
		$found = false;
		foreach ($schema as $field) {
		
			if ($field['element_name'] == $fieldName) {
				$found = true;
				break;
			}
		}
		
		if($found && $context['fields'][$fieldName] != 'on')
		{
			$context['messages'][] = array($fieldName, NULL, 'You must agree to the terms and conditions by checking the waiver box.');
		}

		return;
	}