Hi Computer Courage,
For BackupBuddy questions it is best to post in the BackupBuddy support forum, this forum is more for pre-sales questions. You can access the forum by logging in with your ithemes username and password that you use for managing licenses or to access your ithemes member's page.
BackupBuddy backups are standard zip files. If you are worried about your Amazon S3 account being accessed in ways that you don't like, then look into any extra security settings they may have available to their users.