In many countries public transport is now next to impossible with only cash. You need an NFC enabled device. Often, discounts or monthly subscriptions are impossible if you take an anonymous one. Recharging with cash is time consuming at best, and very hard if the machines do not accept bills. I tried, and eventually caved.
Please enjoy your anonymous public transport to the fullest for me. :(
My take is to convince a whole lot of people to swap their cards with each other. That is, you and I would each purchase a $20 card. Say you and I worked at the same company - when we arrived at work, we'd trade cards.
When I got home, I'd trade my card with my neighbor.
That would enable The Man to cut down on his cash handling expenses, which really are quite significant when you handle quite a lot of coin and currency. But it would make a total rat's nest of any attempt to track transit riders by tracking our payment cards.
I was very amused to realise that it was actually cheaper for me to buy a RFID ticket, run it into the debt limit of $1 and then dispose of it at the end of the trip. Talking to the station staff about it they acknowledged that they didn't like it but that it was perfectly within the law to continue doing so because after all it was still a valid ticket. There's probably room for doing a mix network in places where this loophole isn't possible though, even just a scheme when you see another person adding funds to a zero balance card and it becoming custom to swap your empty one for theirs would do the trick for privacy.
Not to change the topic, but I've been thinking about doing the exact same thing with advertising tracking codes (e.g. DoubleClick). CookieSwappers of the World Unite.
Please enjoy your anonymous public transport to the fullest for me. :(