agreed. And IMHO it's a bad idea for SPF to use the message headers instead of the envelope to do validation as that leads to issues not only with services like

agreed. And IMHO it's a bad idea for SPF to use the message headers instead of the envelope to do validation as that leads to issues not only with services like tempalias, but also mailing lists for example. This is also why SPF failures usually are not treated as enough reason to discard an email.