It would fail in the same ways unless the from address you're using is on their ...

		AnthonyMouse 11 days ago \| parent \| context \| favorite \| on: Deutsche Telekom is throttling the internet It would fail in the same ways unless the from address you're using is on their domains, which is then only a problem for their own customers rather than innocent third parties, and their own customers have the sensible option to stop using their service.