I agree with John,when someone spams or breaches a particular website the admin then has privileges to block the IP range, another person who genuinely want to use the website may also fall in the blocked IP range and may fall in the ban list.But,then one can change the public IP by resetting the modem if it is a dynamic one or request the ISP for a new IP in case of static IP.After the change one can confirm it by using Ip-details.com and then access the particular website