You dont need a bot to do banning, the commands can be used from your war2 client if your account has access to them. There is a hidden admin forum that has a list of the commands, there's also a cheatsheet on the PVPGN site here:
https://github.com/pvpgn/pvpgn-server/wiki/PvPGN-commands . Only iL can set up the time limit since it's a config option for PVPGN and would require a server restart to take effect.
The IPs are not the same, however there is a limit to how many IPs you can get when using the different VPN/Proxy services. Even TOR isnt an unlimited amount. 1hr would be enough to stop mass account creation even with the help of VPN IPs. And getting a VPN to request a new IP isnt an instantaneous action either. It takes time depending upon the service being used. TOR for example, takes about 5-15 seconds to get a new IP while some others can take 1-10 mins. Some even have time limits on how often you can request a new IP.
Another option would simply be to not allow ANY vpn/proxy services to connect at all. I dont know if there are even any legit players that use a VPN/Proxy to connect. If there are, they can probably be counted on 1 hand. Adding such a block is fairly easy but it requires IPTables rules. This would not only stop spam bots, it would also stop repeat offense hackers as well since most people will just connect via a VPN/Proxy if they get banned for hacking, etc. There really isnt any advantage to allowing these types of services.