Safari not warning on SSL certificate hostname mismatch
So, as noted in the update, Safari does actually warn you -- once. 

If you decide to proceed anyway, then for the remainder of that browser session, you need to remember that you're talking to a potentially compromised server, because you will see no evidence of that except by examining the certificate (by clicking on the https/padlock icon). 

However, exiting Safari and restarting it restores the warning. A visit to the compromised site in the new instance of the browser once again presents the warning.