Aility to add register someone who doesn't have an email address

[SoniaL92]

Would be great to include this feature to help users avoid having to maintain two separate lists. 

Would also be great if the list highlights those who do not have email address so that I can see straight away who needs to be notified of event updates/reminders via phone. Thanks!

[Brandon_S]

 This is great feedback, thank you for sharing!