Here is a script that demonstrates the problem. If you uncomment line 4, magic quotes works consistently. If you do not, then some data (or SOMETHING) will cause it to fail most of the time.

<?
mysql_pconnect("","",""); // Must fill in db options
if (isset($adCode)) {
	// echo get_magic_quotes_gpc();
	$sql="INSERT INTO ad_code set sponsor='{$sponsor}', adCode='{$adCode}', cat='{$cat}'";
	echo $sql."<br><br>";
	mysql_query($sql);
	echo mysql_error();
}
?>

Try various data with and with single quotes, and many times magic_quotes_qpc will fail to escape the variables.

I would be happy to provide access to the actual script and server that caused me to notice this problem. Just email.