We outsmarted CSGO cheaters with IdentityLogger

> If a player joins with a different Steam ID but with an IP address that is already banned, the system now re-bans them

This works great until you realize you're punishing innocent players because of CGNAT and IP addresses getting rotated. Cheaters usually know how to get their router to request a new IP address. That IP address then gets assigned to someone else later.

They addressed this in the section entitled "Problematic cases of IP address fingerprinting"

No, not specifically. That section is still written under the misconception that IPs are bound to households, or static networks like university networks. Instead they can swap at the very least country wide (or rather, however the provider manages the IP addresses it controls). Their mental model is just not how the internet works.

By using IP as the ban id they created a system that constantly and regularly banned completely innocent steam IDs, thinking they are somehow linked when a new steam id uses a banned IP, which is nonsense. They just did not notice because the banned gamers did not complain.