Clojurians Log v2

in Chapter 7 there’s the following def mapping keywords to a vector of error messages and error checking functions:

(def order-details-validations
  {:name
   ["Please enter a name" not-empty]

   :email
   ["Please enter an email address" not-empty

    "Your email address doesn't look like an email address"
    #(or (empty? %) (re-seq #"@" %))]})

Is there a reason that for :email we check the whether the string is empty twice, by calling not-empty as the validation function for the first error message and empty? as part of the validation function for the second error message?