Sometimes you might see unsubscribes on mailings that do not have an unsubscribe link in the body of the email. For instance a triggermail or a transactional email.

This can occur, because every Maileon mailing has a "list-unsubscribe header" built in to improve deliverability. Some email clients use this header to provide an unsubscribe button in the client. For example what this looks like on an iPhone:

If contacts click this link, they will be unsubscribed from your account in the same way they would be with an unsubscribe link in the email body.