I don't think that the existence a monthly e-mail should be a factor in which FFP you have an account with, at most it means one click on 'delete' every month, or use rules/spam filter to permanently get them out of sight.

If you really want example of others - try National car rental, I'm unsubscribed from everything on their website and still get e-mails, or Nordic choice hotels, where they have an 'unsubscribe' button in all e-mails but it never works...