When is access_type = Online appropriate? :OAuth2 - Google API
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When requesting OAuth credentials, I can specify the access_type to be Offline or Online.  

Offline:  Response will include refresh tokens that can be saved for later.

Online:  No refresh tokens.

Opting for the Online access type forces the users to approve access to my app each time they login.   Why is that?   Hasn't the user already approved my app?  If this is expected, I'm not sure why anyone will make the users approve access to their Google account each time.

If this is not expected behavior, what am I doing wrong?

As of now, it looks like Offline access is the only practical choice.  Then why is Online access the default?!

Using OAuth 2.0 for Web Server Applications
https://developers.google.com/accounts/docs/OAuth2WebServer