The problem with IP addresses is that many ISPs rotate IPs between customers, especially IPv4 addresses. If an ISP starts running out of addresses, they may hav

The problem with IP addresses is that many ISPs rotate IPs between customers, especially IPv4 addresses. If an ISP starts running out of addresses, they may have to start using NAT. "Privacy" VPNs also do the same (by design). A banned IP may be rotated to a legitimate user under many scenarios. Only ban/blackhole IPs for a limited duration.