This policy setting controls whether users can send form templates along with InfoPath e-mail forms.
If you enable this policy setting, users cannot send form templates as attachments to e-mail messages from InfoPath. Forms templates will have to be published to a network location or installed by users prior to using a particular form.
If you disable or do not configure this policy setting, InfoPath allows users to attach form templates when sending e-mail forms. Note - The form template is only opened directly if the form opens with a restricted security level. Otherwise the attachment is actually a link to the published location.