I suppose that I could setup Outlook on a different computer, putting my friend's "@live.com" ID into the "FROM:" field, and setting "smtp.shaw.ca" as the "outgoing mail-server". So, when sending a message, the "other company" to request to send the "escalation" message would be the owner of the "smtp.shaw.ca" mail-server, namely Shaw. So, it would be Shaw sending the unblock request to Shaw. Really strange configuration, and I doubt that the Shaw Support team would understand this configuration, and I doubt that they would "unblock".
I suppose that I could configure Outlook with two "identities" -- the "@live.com" one and an "@shaw.ca" one. So, sending from one identity would be black-listed, while sending from the other identify would be allowed.
But, that's a lot of hoops to jump through, to show to Shaw the strangeness of their policy.