> there's nothing akin to a software update that would cause the entire fleet of human drivers to start driving badly or unexpectedly all at once.

All, no. Enough to make a difference, easy.

  Black Friday in February!  In-Store offer only!
  $99 Playstation 5 to first 100 customers at each Walmart location!

You can bet there will be a significant increase in people driving badly. edit: Make it Taylor Swift tickets, and you can increase the size of the frenzy.