Google's privacy controls have been very good over the years.
How would you rate Google's use of Location History to tell advertisers when you visit their store in terms of "very good privacy controls"?
"The AP learned of the issue from K. Shankari, a graduate researcher at UC Berkeley who studies the commuting patterns of volunteers in order to help urban planners. She noticed that her Android phone prompted her to rate a shopping trip to Kohl’s, even though she had turned Location History off.
“So how did Google Maps know where I was?” she asked in a blog post ."
"At a Google Marketing Live summit in July, Google executives unveiled a new tool called “local campaigns” that dynamically uses ads to boost in-person store visits. It says it can measure how well a campaign drove foot traffic with data pulled from Google users’ location histories."
"Google also says location records stored in My Activity are used to target ads. Ad buyers can target ads to specific locations — say, a mile radius around a particular landmark — and typically have to pay more to reach this narrower audience." [1]
It is virtually impossible to certify that any given disclosure, no matter how grouped, anonymized, fuzzed, etc. is incapable of being re-associated given other data and time.
I also do not subscribe to the rather expedient definition that your privacy hasn't been violated as long as no human has seen the data. That's an unsupportable claim. As long as my privacy is only a millisecond away from anyone's view on whim, mistake, or trivial disclosure, or some automated system has made some decision that affects me based on my private data I have been violated.
* I have no way of knowing if they actually delete any personal data when I ask them. I suspect that they just don't show it to me anymore.
This is the kind of thing that you go over laborious detail in over privacy design docs at Google to make sure you have it covered.
Source: I'm a Xoogler.