They and can should count users only by updates.
Make a package that is required and only changed upon each release (containing for instance /etc/os-release) and count how many distinct IP addresses download it.
Make a package that is required and only changed upon each release (containing for instance /etc/os-release) and count how many distinct IP addresses download it.
I agree with the core point that tracking users via package updates is a bad idea, but I don't think this specific argument is very great.
Redirecting the requests to the closest existing mirror also obviously drastically reduces bandwidth requirements and should presumably be doable with a few (for redundancy) colocated dedicated servers running efficient server software.
NAT would like to laugh at you
> NAT would like to laugh at you
Not just NAT. On many ISPs, power cycling the CPE changes the IP address.
I don't think there is a more precise way to do it without compromising privacy. Obviously if you are willing to compromise privacy you can send information such as whether the distribution is running in a container or VM and the NIC MAC address and a persistent identifier, but that would be unacceptable since it is not in the interests of users to send that.