That happened to my coworker. All of a sudden windows 10. There was a way to revert it to the older version, but it took some time.
Right, I am not saying that these dialogs did not exist, were not terrible, and some people did not take the time to read them and inadvertently scheduled an update...
However, I am interested in how this happened to an entire business and they did not simply roll back the upgrade? Instead, they chose spend thousands of dollars trying to work around software issues for apparently no gained benefits.
Then it would pop up and say "Hey, do you want to upgrade?" and if you said no it would leave you alone but if you closed it it would assume you were okay with it.
I know a lot of people who woke up one morning and their computer was running Windows 10 without their approval, despite having said 'no' to previous questions.