When you login to Passpack via the Gmail third party login, Passpack uses IMAP to ping your account and authenticate you. No email is read, just a ping to authenticate you.
Alas, this is a feature is causing panic with Gmail’s ”Suspicious Activity” alerts. So we’ll be removing it as an option in the near future. Read this Help Center article for more info.
If you have already set up your Gmail as a 3rd party login option, you may continue to use it if you wish. Alternatively, you may choose to switch to Google friend connect.