I'm confused; was no consent required? Apple's setup very clearly explained what would happen and needed affirmative consent before it could be enabled. Seems insane that Google would've just... turned it on for everyone.
I was on the Play Store and was responsible for implementing the Play Store side of this process.
No, we did not install it without informing the user.
Play Services would check to see if there was an app available for the user's region that used the contact tracing library. If it was, they'd hand it off to the Play Store which would explain some stuff and give the user clear buttons to opt in or out. I can't recall the exact text, but it was along the lines of "Yes I want to opt-in to contact tracing" and "No, I don't want to opt-in to contact tracing". The yes button would have been some bright primary color (probably green) and the no button would have been white, per UX guidelines.
We ran detailed metrics on this to see what users would do. Some huge percentage of users would scroll to the end and click the colored button in 5 seconds, probably just to get rid of a screen they didn't care about.
Also, the location warning is unfortunate. If you have an app with Bluetooth access then you get this warning. The reason is that BLE 4.0 beacons are so cheap and easy to spread around that you could use it as a positioning system. In Manhattan you could cover everyone who walks past a subway entrance for a couple thousand bucks easily. So the decision was made that this was akin to location services. It's certainly not clear to the end user, which is a shame.
https://arstechnica.com/gadgets/2021/06/even-creepier-covid-... says "COVID tracking is not enabled unless users turn it on".