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August 1, 2016. The day I'd been dreading. Sydney had finally abolished paper train tickets and I was getting ready to erase my identity.

The Australian state of New South Wales had been gradually transitioning away from paper tickets for more than two years. In the interests of entering the digital era, Transport NSW introduced the new 'tap-on, tap-off' Opal card. A contactless travel card, named after Australia's distinctive rainbow-hued Opal gemstone, it's similar to London's Oyster card and San Francisco's Clipper.

Welcome to the future! No more paper tickets! Top up your Opal card online! Set up a direct debit, download the accompanying app and track your spending, you mouth-breathing luddite -- this is the 21st century!

But if this was my ticket to the future, I was not on board.

I'm not against going digital. I have an email account. I use internet banking. I have even foregone my family's tradition of using a cool, damp sack to store milk in favor of putting it in the "refrigerator."

But in the context of an increasingly pervasive culture of state-sanctioned digital surveillance in Australia and across the world, this smart card smarted.

Surveillance state

In 2015, during the transition from paper to Opal, Australia passed sweeping new data retention laws. These laws required all Australian internet service providers and telecommunications carriers to retain customers' phone and internet metadata for two years -- details like the phone number a person calls, the timestamps on text messages or the cell tower a phone pings when it makes a call.

Suddenly, Australians were fighting for the right to stay anonymous in a digital world.

On one side of the fence: safety-conscious civilians. They argued that this metadata was a powerful tool and that the ability to track a person's movements through phone pings or call times was vital for law enforcement.

On the other side of the fence: digital civil libertarians. They argued that the data retention scheme was invasive and that this metadata could be used to build up an incredibly detailed picture of someone's life.

And sitting in a barn two paddocks away from that fence: me, switching out burner phones and researching VPNs.

When it emerged that police had the power to search Opal card data, track people's movements and match this to individual users, it was the last straw. August 2016 rolled around, paperless tickets were phased out and I hatched my plan.

The Black Opal.

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Going off the grid

The concept of the Black Opal is simple. Buy your transport card. Pay cash. Top up with cash (preferably in a new location each time). Never register it. Never link it to your credit or debit card. Live off the grid. Stay away from The Man.

I went dark in early 2016, when I needed to catch a train through the city. It was simple enough. Most Opal cards are sold at newsagents or corner stores -- the card itself is free, and you fill it with credit in increments of AU$20 or AU$50. I bought a card, added credit and walked away into the night.

I tapped on at Central Station, just another faceless commuter. But as I walked through the meatspace, jostling with peak-hour travellers and being thrust into the armpits of sweat-addled corporate lackies on my packed train, I knew I was safe. Deep in the Transport NSW matrix, I was unidentifiable.

A few weeks later I needed to top up. No problem! I jumped off the train at [REDACTED] station and filled my card at the [REDACTED] across the road. I paid [REDACTED] for one Opal top-up, two [REDACTED] bars and a copy of the weekly [REDACTED] Times. Faceless, nameless bliss.

Then the problems started.

Always bet on black

I'm all for escaping the Orwellian nightmare of the modern surveillance state. But when you rage against the machine, you still have to associate with the bulls on parade.

All the top-up machines at train stations, light rail stops and ferry terminals were card-only affairs. One tap on that baby and you were back in the system.

So, if I was busing downtown for a work meeting, I'd have to factor in extra time to get to an ATM, get cash out and then find somewhere to top up my card. Running for the train with friends, I was the one who had to divert three blocks, change jackets, burn off my fingerprints and find a nondescript corner store to top up.

Here's what I learned.

Ian Knighton/CNET

No one likes the paranoid one.

I constantly harass my friends for signing up for rewards cards that track their spending. My email address (that is, my real email address, not my burner address) doesn't use my birth name. I am no fun at birthday parties, but you'd never know it... mostly because I won't reveal my actual birthday.

But I'm not alone. For someone who was mostly educated through the received wisdom of Hollywood movies, I learned a lot about what The State could do to me. I watched "The Net" as if it were a documentary. I didn't brush my hair for weeks after watching "Gattaca." I spent months walking around my house, narrating my life after watching "The Truman Show," just to give Ed Harris more material to edit.

I wish these stories weren't true. But in the grim near future of "Demolition Man" I know I would be the one hiding in the bathroom, away from the countless surveillance cameras, trying to stop people stealing my eyeballs. (At least I'll have plenty of time to work out how to use the three seashells.)

End game

I finally came undone last week. Racing for a flight, I forgot about my Black Opal. I'd had an unusually busy week on public transport, and my balance was low. On the train to the airport terminal, it hit me. Did I have enough money on my card to pay the AU$17.76 tap-off fee that they use to gouge tourists at the airport?

As I rode up the escalators and the exit turnstiles came into view, my heart sank. No ATM. No cash in my wallet. Just a row of bright green Opal readers and a top-up machine. Card only.

Today's the day. After 3 years living off the grid and topping up my Opal card with CASH ONLY (unmarked bills, small denominations) I was 9 cents short for the $17 fare to the airport. I had to top up with my EFTPOS card. It's over. The Black Opal project is dead. pic.twitter.com/TXKahak75t — Claire Reilly (@reillystyley) March 8, 2018

With one trip, my years of off-grid living were undone. (And yes, it was two years, not three. My how time flies when you're madly tweeting like a paranoid vagrant at the airport.) I slumped against the top-up machine and swiped my debit card. I was just 9 cents short, but it cost me so much more than that. My Black Opal was dead.

$19.84

I bought a new Opal last Monday. Hidden in my wallet, it represents the freedom to traverse the city undetected. I'll use the last few dollars on my Tainted Opal, but even though you'll see my human suit on the train, that won't be the real me. The real me is already beneath the mainframe: stockpiling cash, buying a collection of cheap nylon wigs and mapping out a network of newsagents with red string so I put all my money on Black.

I know my spending can be tracked on my debit card. I know virtually all my personal information is now in the system, thanks to driver's license records, electricity bills and that government-sponsored data sweep they call "the census." Hell, I even know my telco can hand over a map of every cell tower ping my phone makes as I cross the city on the train.

But as long as I'm carrying my Black Opal, there's that little shred of liberty. If this the hill I die on, at least you'll never know how I got here.

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