People: It's "viruses", not "virii", fer cryin' out loud!
...and many others.
*grinds teeth in frustration*
And BTW it's "waive", not "wave". Sorry, this one's not intended to be a rant, just thought I'd mention it.
@Michael C: You know, buying a virus scanner subscription is not the only way to secure a system. And it's not the only way to clean up an infection. In fact, installing a virus scanner after-the-fact is generally useless for any virus worth a damn.
Wiping a system clean and re-installing the OS is VERY affective at removing a virus and does not require a purchase. How do you take a screenshot of that?
Throwing away a system and buying a new one is just as effective and doesn't require the purchase of anti-virus software.
There's also ClamAV.
I find it interesting that your scheme considers proof of the effort to be superior to the actual effort of cleaning up. Beware of unintended consequences, my friend: people WILL game the system. Adding more rules to prevent it will just make a mess of things. Apply the KISS principle here: if you can detect an infection, you can detect when it's been cleaned up. Giving people an "A" for effort is all very friendly but doesn't solve any problems, because the infection is still there, and it complicates the situation by requiring elaborate methods for providing proof and locks out some very effective eradication methods. If the customer wipes out his OS and starts over, and his infection goes away and he stops spamming or botnetting or whatever, by your scheme you would continue to charge him!
What if he decides never to acknowledge your E-mail? He gets a free ride.
It's also a very elaborate scheme for making the ISP keep detailed logs, provide hands-on analysis, notify, verify, and so on.
I think your heart's in the right place but I think you're over-thinking this one. By bending over backwards to give the individual the benefit of the doubt you've put a tremendous amount of effort on the ISP and made it impossible to employ. Don't be so concerned about the rights of the individual that you forget the rights of the community.