HALLOWEEN15
Just received a sms message from SYD Airport. They are offering a 15% off on parking.
Book by 9/11, enter by 15/12, subject to avails&excl apply
Code: HALLOWEEN15.
Note that if you cancel your existing booking they will not refund you the credit card payment surcharge, but in my case, it's still cheaper to cancel and rebook.
That's pretty spooky…