Right. I understand that having that option lets you mitigate some problem. Can anyone expand on what this option does and how it mitigates the problem? Did I miss something from the blog post?
edit: worth noting that there are obviously other ways a hacked Mandrill/Mailchimp account could be abused. This just shuts down one of the major abuses you could perform.
Those are two entirely separate companies (unlike Mandrill and Mailchimp which is the same company.)