Yes you are right it is very hard to stop exploiters, but comparing blizzard to LDW is a bit different being that 90% of blizzards game access a game server. It is a bit easy to detect them since it directly affects the data stream and it can be found pretty easy.

As for the save file, it saves as a pts. save file, now if im not mistaken that would be a file from Infinity Engine Game Tileset?
If it is let me know I can pm you a few ways on how to eliminate them hex editing the pts file.