If you look at https://track.emirates.email you will see that it isn't emirates either, but a service provided by Mandrill, an add-on for MailChimp, and the cert is valid for https://mandrillapp.com. Surely they could have figured out how to use SNI.
The fact that your mail client / embedded browser takes you happily to sites with broken certs, giving them a tracking token (and in this case, total access to your booking) is also quite a problem.