Email can not be set to required

In commerce_registration.checkout_pane.inc it is checked whether the mail address is required - only then the email is validated.

As for registration-7.x-1.x-dev the email address cannot me set to required.

Thus this line (181ish) will alway return false.

$mail_is_required = $form['registration_information'][$prodkey][$prodkey . '-reg-' . $i]['anon_mail']['#required'];

For my setup I changed this to:

$mail_is_required = TRUE;