Australia’s Internet Industry Association (IIA) is working on best practices for isolating computers with bots on them (http://iia.net.au/index.php/initiatives/isps-guide.html)
At the same time, the Internet Engineering Task Force (IETF) is also drafting a document about the same thing (http://tools.ietf.org/html/draft-oreirdan-mody-bot-remediation-03)
If these recommendations are adopted then people who have bots on their computers would have to get their computers cleaned up before their ISP would allow them to surf the web. The idea has been around for quite a while, however issues such as cost and privacy have been the main barriers to the plans.
I do think it is likely that eventually your ISP will adopt an approach to identify customers who have bots on their computers and then limit their web access to a site that can help them clean their computer. I think it will be a few years before any major ISPs actually have full implementation of quarantining infected users, but the day may come that you won’t be able to surf the web if your computer is infected.
Director of Technical Education
Author ESET Research, We Live Security