When creating tables, consider creating a field named 'deleted'.
You might want to make this the last field in the table.

  `deleted` tinyint(1) unsigned NOT NULL DEFAULT '0',

This facilitates flagging records as deleted, via a trigger.

For List mode, display only records whose default value is 0.
Below the table definition, filter the selected records with:

   $opts['filters'] = 'deleted = "0"';

The generated field array for 'deleted' should resemble:

   $opts['fdd']['deleted'] = array(
      'default' => '0',
      'input' => '',
      'name' => 'Deleted',
      'options' => '',
      'required' => true,
      'select' => 'T',
      'size|ACP' => 1,
      'sort' => true
   );

Comment out the field array. You don't really want it to appear in the form.
In place of the above field array, add a trigger:

   $opts['triggers']['delete']['before'] = 'triggers/mark_as_deleted.TDB.inc';

Contents of the trigger file might read as follows:

$query2 = sprintf('UPDATE %s SET `deleted` = "1" WHERE `%s` = "%s" LIMIT 1', $this->tb, $this->key, $this->rec);

if($this->MyQuery($query2)){

   // success

   return false;

}else{

   echo "\n".'<p>'.htmlspecialchars(mysql_error()).'</p>';

   echo "\n".'<p><a href="javascript:history.go(-1)" onmouseover="self.status=document.referrer;return true">Go Back</a></p>';

   exit;

}

A utility such as phpMyAdmin can subsequently be utilized to
reactivate "deleted" records.

TEST THOROUGHLY BEFORE IMPLEMENTING ON A WIDE SCALE.

The `deleted` field might alternatively be an ENUM('Y','N') field.