If you had a bank card from a certain big Austrian bank ("Erste Bank"), that day you could not pay by card, nor get money from the ATM; basically you were locked out. Safe to say, chaos ensued for a number of hours, as many people had too little or no cash with themselves.
I remember being at a cantine where a long queue had formed with people with the trays wanting to pay and cantine staff running desperately around with "name lists" to register people in return for their promise to pay when service resumed, which it did in the afternoon.
A cashless society is much more prone to black swan events.
Surprisingly I was told by acquaintances that the incident didn't make headlines the next day, and was casually mentioned among other political scandals.
One year (one day actually) in a decade comes close to the very definition of a black swan event. :)
And yes, people will opt for convenience, not rational behavior:
In some cases, that black swan event will cost more than the cost of inconvenience. For example in the US, it is "inconvenient" to retrofit buildings to make them earthquake-resilient, but when the earthquake black-swan hits -and it will hit for sure, the only question is when- damages will be huge, and costs as much as 4 times higher than investments in earthquake-resilience today: https://www.optimumseismic.com/earthquake-preparedness/what-...
I'm sure Kahneman & friends have a name for this cognitive bias that somehow makes it hard for humans to correctly assess the risk and cost for black swan prevention (sometimes, because of the rarity, these computations in principle can't be made). This type of cognitive bias seems also connected with difficulties humans have in thinking on time scales that exceed their own life spans ...
Lets be honest - not having cards working for a day is not the same as earthquake. Sure people will miss trains/rent etc. 1 or 2 business may go under but for 90 % people all will be fine. Heck I am sure if many shops/metro will be free if some one like erste bank or Sparkasse does not work.
