Go to donotcall.gov and go to the rules section. When you get to the rulings, do a search for "face" and you'll see exactly what I'm talking about.
It's under the exemptions section and says:
"Telephone calls in which the sale of goods or services or charitable solicitation is not completed, and payment or authorization of payment is not required, until after a face-to-face sales or donation presentation by the seller or charitable organization, provided, however that this exemption does not apply to the requirements of...." (and it goes to list requirements to not be abusive, etc.)
Dang it, there used to be some very clear wording that calls for setting appointments (i.e., not making a sale) was included in the do not call rules. Looks like they may have reversed course in the 2009 updates, which I never bothered to read, thinking the robocalls stuff didn't really apply to me.
I haven't had a chance to go through this in its entirety, probably never will, but it is an interesting change. A quick google of this shows many 'experts' recommending caution on exploiting this loophole, but almost confirming that yes, it has been allowed. Hmmm, interesting.
Dan