You shouldn't ban someone just because they have the same range as a hacker, it's very possible that they share the same range. You should be sure they are the same person. Like for example, you ban someone and someone rejoins the next minute with the same range, then that's fine, coz it's probably the same person, but checking the ban list and banning anyone with the same range? Nah, it's stupid, loads of people share IP ranges.