That's really interesting and insightful, thanks. But if I can offer a suggestion, it sounds like you were blocked by proofpoint while actively trying to spoof

That's really interesting and insightful, thanks. But if I can offer a suggestion, it sounds like you were blocked by proofpoint while actively trying to spoof legitimate traffic in order to avoid detection by proofpoint. That's hardly "no reason at all," despite your having the best of intentions.