Should I have told?

In my Computerworld article "5 Easy Steps to Career Suicide," I relate an incident in which I call a client company and reach a person there that I haven't done work for previously. I tell that person that "Carl" (my client contact, and therefore a co-worker of this person) has been pleased with my work. The person said in response, "Why should I care what Carl thinks?"

In other words, one person in the organization is "dissing" another person to me, an outsider. This remark demonstrates a lack of unity and professionalism on the part of the person I called.

As you can guess, that call really went nowhere. Afterwards, I didn't do anything in follow up. However, I'm wondering if I should have told "Carl" what this person said. On the one hand, it's good for him to have a "heads up." Also, that person never really expected that remark to be confidential. On the other hand, might "Carl" "shoot the messenger?" And, does it make me a tattle-tale?

What do you think?