OK, so this just happened to me and this post is not to be intended as a guide or even a recommendation!
A customer called me with a serious issue that mails were not being sent to people outside of his organisation. upon connecting to his EMC I received a message that one server was running in trial mode with 119 days left. So that means that it had just been installed the previous day. It turned out that the so-called trial server was actually a helpdesk PC running windows 8.1. The tech (who was also a domain admin – wich he of course shouldn’t have been) wanted to install the Exchange management console.
Now Exchange should not even install on windows 8 but in this case (guessing 8.1) exchange did not recognise that this was a workstation OS and offered the option of installing all components. The tech who was not familiar just clicked next and installed a full blow all in one copy of exchange 2010 on his PC. This ofcourse led to mail flow issues. Uninstalling the exchange fixed everything but I couldn’t believe my eyes when I saw exchange 2010 installed on windows 8.1.
So my advice to you is
2. Don’t give a helpdesk tech domain admin privileges.