re read my last reply
All form Processing must occur on the page specified as the Action.
Server validation is a type of form processing. Therefore, server validation must be applied to the page specified as the action of the form.
In the tutorial, the action of the form on the checkout page is set to post to the confirm page, that is why Anna is adding the validation to the confirm page.
Both Universal Email and Server validation are processing the form, so both need to be added to the page specified as the action in the form tag.
just make sure that the server validation code comes before the Universal Email code so that the email will only send if validation passes.