Diving into form submission code is always fun. Could be done with:
PHP Code:
$table_strings = array("[table]".chr(10), "[tr]".chr(10), "[/tr]".chr(10), "[/td]".chr(10));
$table_replace = array("[table]", "[tr]", "[/tr]", "[/td]");
$submit_text = str_replace($table_strings, $table_replace, $submit_text);
or similar before the database submission, probably inside whatever function is used to clean up the text.