Force admins and resellers to specify an contact email when creating new accounts

It came to my attention that the contact email is not a required field when you create new accounts. I observed in my servers that this resulted in resellers not setting a contact email for most of their new accounts. Is this the expected behaviour or is it a bug? Because if there is no specified contact email, nobody will be warned when a resource on that account is about to be over quota.

If some people have reasons to keep this as a non required field, then a good idea would be adding this option to the Tweak Settings: "Contact Email Required for every new account", with the default value set to off to respect those people who don't need this option enabled. Otherwise, please default to on.

Any thoughts?