From the linked article:

The cash booths remain unattended, but all were equipped to detect e-tags in cars which pass through, he said.

So to actually get free toll, you need to

1. Hide your e-tag in your grove box.
2. Drive pass the cash booth lane.

But even that there’s no guarantee that they won’t photograph you and charge you later on…

i read in the MX that they will clear any fines from not paying at the booth, so thats always reassuring.

its not very fair to fine someone when the person at the booth isnt accepting money lol

No such luck for Melbourne - All tolls are sucked directly of you (account)!