This policy setting controls whether templates sent with InfoPath e-mail forms are cached locally.
If you enable this policy setting, InfoPath does not cache the form template attached to the mail item; instead, it caches the form template from the published location. This requires restricted forms to be published rather than just sent by e-mail. Users can still be sent forms by e-mail, but the form template must be available from the published location.
If you disable or do not configure this policy setting, InfoPath caches form templates when they are attached to a mail item that is recognized as an InfoPath e-mail form. When users fill out forms that open with a restricted security level, InfoPath uses the cached version of the mailed template, rather than any published version.