We registered a few domains and get the same thing, I think
it's something that people are going to have to live with. 
I read your response and totally agree. I'm just saying that your dollars not being spent with someone will probably not result in the calls stopping. Advertising and marketing dominates this planet now, and people make big money by selling "lists" to organizations making a buck. Not saying these people didn't get it directly, but it should not be expected to stop unless there is a do not call registry (as I would think those guys would fall under a telemarketing agency). I could be wrong..
I'm pretty sure you have to sign a AUP or something to get access to the
mass whois tool with ARIN, I'm just not sure of how they enforce what
people are actually doing with the list.
I won't pretend to know how it's getting out there. Google your email address in about 10 minutes and see this conversation in 10 different lists.
As Mark mentioned, this list has a lot of valuable eyes looking at it - so it's often a <insert snake oil o' the month> sales guy's wet dream. On the upside, solarwinds sent me a random 10 dollar amazon gift card a few weeks back so not all is lost.. 