Anyway, I agree that these users were committing fraud, but why ban me? I didn't condone (or even know) what they were doing until after the fact. The correct thing for AdSence to do here is to identify the offending IP addresses, cancel the credit accumulated by said IPs, and let me continue supporting the program on my site.
Because, explicitly or implicitly, something you were doing was encouraging people to defraud advertisers through your website. The way to stop this is to eliminate the cause (the person/site encouraging the fraud) not the symptom (today's batch of site visitors). Multiple people don't start engaging in multi-day click fraud behavior randomly -- something sets it off, something as innocuous as a forum post encouraging it or text near the ad that says "this project supported by ad clicks" -- but there has to be a catalyst, and that's the thing they're putting an end to by suspending an account.
That's a pretty bad thing to say about someone without any proof whatsoever. If users decide to 'help' you that does not automatically mean that you 'explicitly or implicitly' encouraged them to do so. People will do the strangest things without any prompting.
Technically this exposes a weakness in Google's program, after all any competitor could do this to you resulting in the banning of your account.