i think the point is that you're not sending these docs over email, and they never actually trigger the filter they might trigger. if you're emailing docs containing the "don't email me" trap often enough that you get your account flagged, you've got bigger problems.

That's a risk, but not as big a risk as a report escaping quarantine.

It usually takes more than one email unless its flagged as having malicious contents.

Indeed. My comment was meant as a guess on what they put in their watermark.