Abuse rate limiting often relies on the scarcity of IPv4 addresses. If, for example, you limit a user to one concurrently used account per IP (which some gamin

Abuse rate limiting often relies on the scarcity of IPv4 addresses. If, for example, you limit a user to one concurrently used account per IP (which some gaming sites do to discourage cheating/griefing by one person playing multiple players at the same time), this breaks. This can also be revenue relevant if e.g. the ability to have multiple accounts per IP is a paid feature.