Did the same experiment similar results!
I am affiliated with a small international charity.
we have a weekly mailing list of about 10thousand people if that is any idea of the size of the group. I own my own separate domain so i did the exact same thing i used a unique email address for a contact on a minor page.
I average one or two emails a day and that web site was up for 6 months and has not been up for 3 months.
I agree that there should be more work by authorities to track down and stop these people but with 911 and many other "priorities" making sure we don't get too many annoying emails is not a big deal!