Membership: Can Multiple Emails Login to the Same Account?
You may sign in to your account with only one email address—the Login Email. Secondary emails in the same account will be CC'd on communication sent to the account, but they cannot be used to login to it.
For cases where multiple people want to sign in to the same account, consider obtaining an email account used strictly for site access, and then give everyone the credentials to both the email account and the SwimOffice account. That way no one has to give access to their personal email account.
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