Privacy rules for setting user IDs with Google Analytics for Firebase?

Question

I have an iOS app in which I'd like to use Google Analytics for Firebase to associate events with user IDs. The setUserID method documentation states:

Sets the user ID property. This feature must be used in accordance with Google’s Privacy Policy

But I am unsure exactly where in the Privacy Policy the rules are outlined. There is other information on the Analytics support site as well.

I am assuming that only non-identifiable user IDs are allowed, eg. a randomly generated, unique string for each user (UID3515). Can anyone confirm?

Answer 1

They are concerned with the collection of the Personally Identifiable information (PII).

Quoting from the docs:

You will not, and will not assist or permit any third party to, pass information to Google that Google could use or recognize as personally identifiable information

See the Privacy section in the Terms of Service for more details.