No, because look at example. I got user who 1 year on my forum. For this time he got about 100 different IP adress (perhaps it all his possible ip). So if he will try register new account it will check with 100 different ip and maybe some of them will match and he cant register. But if i ban all this IP, so he will reboot his internet and get this IP until he receive a new IP which is not in ban.