[action] => test
[city_name] => Orlando
[delete_me] => -
$_REQUEST['delete_me'] = "";
In addition to what halfdan said, you should probably be using
$_POST or equivalent, unless you really do require it to be that ambiguous.
Taking values from
$_REQUEST can make XSS that much easier... when you want POST values and a malicious user just appends them to a query string.