Android: get user ID without requiring scary (for user) permissions?

Question

In order to manage user preferences, at present I\'m grabbing the google user name (effectively the email address they\'ve registered to the device) and using (a hash of) that a

Answer 1

You can use a Google advertising ID as a UUID, but it's not cross-device(yet?):

https://support.google.com/googleplay/android-developer/answer/6048248?hl=en

That'll at least get rid of the scary permission request.

I don't believe Android/Google has a cross-device UUID that doesn't require permission, though Doubleclick by Google supposedly was developing one.