The issue was that people couldn't connect the smartphone app that can be used to unlock and start the car. A key fob or key card can also be used but not everyone carries those as a backup, so without the app working they were locked out of their cars.
This is what happens when you rely on having network connectivity and an app working.
Here's the BBC's take on it - https://www.bbc.co.uk/news/technology-59357306
Which is why when I was using my phone and smarkwatch to make contactless payments, I still had the physical cards in my pocket.
Why anyone would rely on a smartphone app for something as important as unlocking their car is beyond me. I mean what if you drop the phone in the toilet, get mugged, the battery dies, etc?
This explains the pandemic protests in a nutshell, people who are so entitled, with zero concept of having contingency plans or compromises to protect their and other peoples safety.