Unique is case sensitive but email domain isn't
Email domains are not case sensitive but the unique constraint in Django is, so
EmailField(unique=True) allows for duplicate emails to be registered in the database
"Email domains are not case sensitive"
RFC 5321 states that the mailbox in mailbox@hostname of an email format is case-sensitive.
firstname.lastname@example.org are therefore different email addresses (the domain is case-insensitive).