Not having signed up I didn't realize the security implications until I read that link, not good.
Quote:
...In other words, signing up to Pokemon Go with your Google account gives the developers the ability to do the following:
• Read your emails and send emails from your account
• View, edit or delete your Google drive documents
• Browse your search history
• Browse Maps navigation history
• Access content stored in Google Photos
As security expert Adam Reeve pointed out, the access to your emails poses an extra security risk that extends beyond Google accounts....
Who would agree to that? Someone who maybe doesn't read the agreement???