In a comparable product line, there is an option to register (prove ownership of) a URL, and then all email addresses with that URL are locked to our account only. What is happening is employees are creating their own free accounts outside of our account, and then they have to adjust or delete the email address for us to apply the correct email in our account. In theory this could even be used as a denial of service attack if someone just started guessing and taking our email addresses (can we even dispute ownership of that email to regain a unique address?).
Just a thought, but I feel like it would be good to be able to have that reserved to our account only.