Instead of teaching them a lesson, why don't teach the public to stop blindly clicking e-mails and ads that they have no idea who or where they came from. These people will be around forever as long these people keep doing this. I understand there are "bugs" in our software in which these crackers will and do exploit, that is why it is a good idea to leave automatic updates on on all OS, AV and firewall software.
I think the last time I read that a vanilla out-of-the-box Windows XP station put on the internet, it would be compromised within 15 minutes. It is probably less now. At least Microsoft is attempting, albeit loosely, to lock down the OS with a generic firewall built in. However, it doesn't matter if the public doesn't know how to use it.
While every just screams "Just go and get Linux/Unix.. and all of your problems will go away!" is sadly mistaken if you believe that to be true. Besides a sleuth of enterprise software that is currently incompatible, if it were the other way around, Linux/Unix with the market share and Microsoft without, then our problems would be mirrored. Why do they target Windows? Not because it is faulty, because it is the accessible. We in the Open Source crowd find security vulnerabilities and bugs all the time in Linux/Unix circles of distributions but, how many stories do you here of those being attacked, cracked and taken over like you do windows? Rarely, if ever, because no one is trying to exploit it. It is easy for any pimpled faced kid and any of the number of so called "Network Administrator Tools" to find a windows box scan for vulnerabilities. However, to search for those Linux/Unix boxes with that one open port that can be infected, will turn tits up. Not because people plugged the whole, because there are not many around.
Sigh, it will never end until the PUBLIC is educated. However, I don't think that grandma and grandpa could really be educated or even care. As long as they can e-mail and surf their genealogy, they could care less if unknowingly their computer compromised.