symbols

I have this code in a model in a Rails project.

  validates :name, presence: true, on: :create
  validates :email, presence: true, format: { with: URI::MailTo::EMAIL_REGEXP }, on: create

Let's put it in an Author model:

class Author 

When retrieving a list of all of the authors without email addresses (because, well, we are cleaning up these things) with this line of code:
  authors = Author.where(:email: nil)

... two new blank authors are created at the WHERE query.  Both of their names and emails are blank.  This is absurd!
Find the bug.