Even if the user is aware, it can be very annoying when stuff changes.

It's like someone comes into your house and changes the furniture.

Makes me think of “terms of service can change at any time” type stuff. At least we get some email about it and have a paper trail but who can keep up

In this case, this is a new feature for a new app. They didn't change anything. The setting didn't exist before, nor did the app

They auto-installed the app on everyone's phone, and auto-enabled this feature on everyone's phone. The feature sends my location to someone else when they are nearby and using the app. So even though I deleted the app, other people nearby could still receive information about me because I haven't disabled the default toggle I never opted into in the first place.

It's almost suspiciously malicious that they auto-enabled this feature and auto-installed the app for everyone at the same time.

Installing a new app onto a phone absolutely changes the phone. This app was packaged in an OS update.