That is the kind of flawed logic I keep running into with them and hence my
frustration. You don't have to be an IT guy to know that if someone receives
something and then it disappears, they somehow lost what they received. duh!
One other though occurs to me: User Agent string. All email clients stamp
their messages with a User Agent string in the headers. My favorite is
Pegasus Mail:
| X-mailer: Pegasus Mail for Windows (4.41)
My mother prefers MS Outlook Express:
| X-Mailer: Microsoft Outlook Express 6.00.2900.5512
I have played with Windows Live Mail:
| X-Mailer: Microsoft Windows Live Mail 12.0.1606
And even with Mozilla Thunderbird:
| User-Agent: Thunderbird 2.0.0.12 (Windows/20080213)
| X-Mailer: Unknown (No Version)
Yes, both of those appear in Thunderbird email headers.
Even the Opera browser has an email client built into it:
| User-Agent: Opera Mail/9.24 (Win32)
Some spam filters look for certain User Agent strings, and filter the email
based on them. Could happen either on the Embarq, or the Comcast email
servers.