wiiki - UndoEditsByIpBot

It's not that difficult to create a bot / script that undoes edits made from a list of IP's / IP ranges.

What's needed, basically, is to:

check RecentChanges for edits by the targeted IP's
use EditCopy to quickly revert the edit
'touch' the page using a different IP to purge the EditCopy

In PseudoCode rather than real code (lest any one tries and uses such a contraption against this site):

Every couple of minutes:
{
  Fetch RecentChanges from the server
  For each IP on list:
  { 
    filter for IP address
    For each mentioned page not removed:
    {
       Send http request for EditCopy
       Send http request to click Save button
       From different IP address:
       {
          Send http request for Edit
          Add or delete one whitespace character (null changes are rejected)
          Send http request to click Save button
       },
     },
   },
},

The above is easily done in PerlLanguage, JavaScript or similar. A bit harder, but certainly doable, in C++ or similar.

More complex versions could possibly:

Detect earlier changes by an IP and revert to a version before that
Instead of reverting to before that version, merge those changes out, leaving other people's contributions intact
Detect spam cleanups and leave those alone, even if done by the targeted IP

Detecting any edit by user JohnDoe coming from any random IP and deleting those while leaving a consistent version of the page is very possibly AiComplete, and could only be done by a human masquerading as a bot.

But what even the simplest version of such a bot would do, effectively, would be denying edits by a particular user or group of users, since most of us have either a fixed IP or an IP within a certain range.

MichaelSparks seems to have used a similar approach in fighting spam (since a lot of spam seems to come from a limited range of IP's).