Yes. Sometimes, mischievous players are supposed to be temporarily banned from dedicated servers (e.g. for a period of 40 years), but bans are bypassed thanks to benefits of dynamic IP. It is possible to ban a range, but such a solution has serious disadvantages: it's possible that a few innocent players will get banned - which could be especially troubling in a server that is supposed to host JDC events - and ISPs not always (if ever) care to mention somewhere in the Internet what IP ranges belong to them, so it's likely that banning two known ranges will leave one or more unbanned. Surprisingly, it works the other way around, that is, having IP of a person you can easily check their ISP, which is often the only thing one needs to do to be assured that a suspiciously acting player with an unfamiliar nickname is the person they suspected them to be. Another case, sometimes occurring along with the former, is impersonation of existing players; I doubt I need to explain. Since player's IP is displayed when they happen to stand on the wrong side of a kick/ban command, I'm pretty sure it's not meant to remain a strict mystery to remote admins with access to those. Even if it is, it can be prevented thanks to admin.ini, so implementing the command shouldn't cause trouble.