When using drupal_get_query_parameters(), should I still run values through filter_var() or check_plain()? When absolutely needing to take in query string values, I'm using drupal_get_query_parameters(). However, is it still a good idea to run values through check_plain() or filter_var(). Or does this drupal function automatically take care of data sanitization for me?

For example, is the filter_var with FILTER_SANITIZE_NUMBER_INT a good idea, necessary, or redundant? 

&lt;?php
$params = drupal_get_query_parameters(); 

// get dept name if exists in query string
if (array_key_exists('exposed_filter_a', $params['field_department_tid'] = filter_var($params['exposed_filter_a'], FILTER_SANITIZE_NUMBER_INT);
    $expfilter_value = taxonomy_term_load($params['exposed_filter_a'] )
}
drupal_get_query_parameters() doesn't perform any sanitisation of vars at all.

If you need to validate the incoming value, or filter it for XSS before it is outputted, etc., you'll need to do that as normal.