I like this.  We got a bunch of *ubuntu disks for ITEC, but people had to come to the booth and indicate interest in Linux.  It's not like we stuck them under windshield wipers in the Wal-Mart parking lot.

The coupon should also say that you're not just getting the disk, you're getting a network of people who will help you learn how to install, configure, and use it.  That's the extra that you don't get when you buy shrink-wrapped software.