I think a more effective "alphabet" would be amount downloaded by that IP. Start with the people who download the most first and then publicly announce what the

I think a more effective "alphabet" would be amount downloaded by that IP. Start with the people who download the most first and then publicly announce what the limit was each week. The people who download the most are the most likely to be aware of this scheme so you mitigate against the problem of ignorant users. Also, in this scheme, the inability to track every download is a virtue, not a vice. Say they announced that the limit last week was 600Gb and you downloaded 500Gb last month. you decide to download 250Gb this month just to be safe but of the 500Gb you downloaded, they only tracked 300Gb so you're bringing the limit lower for next month even though you're nowhere near the boundary case.