I was randomly trying coupon codes and just came up upon this, like last years code I changed the code INDUSTRY18 to 19 and it worked. Not sure the limit claimed for the ticket. Unfortunately for Melbourne you get an error when entering the code. For Melbourne, select Flexi-Tickets and then apply code.
https://tickets.lup.com.au/cake-bake-sweet-sydney-2019#
YOUR COUPON CODE IS VALID
INDUSTRY19 Industry FOC code x 2
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Melbourne works.Thanks