If someone really wants to cheat at your game, why not just let them? It doesn't hurt anybody.
Plus for certain things it's kinda fun. After beating Liberty City Stories and playing the hell out of it for a couple months the game just sat and collected dust for a while. I downloaded cwcheat and got another couple months enjoyment out of it, just goofing around. Flying around, making obstacle courses, doing crazy stunts, whatever.
I don't know, I just think that if someone really wants to go through all the trouble to download a tool to hack your game just to get infinite health or whatever, might as well let them do it. If they're doing it to beat the game, they're not letting anyone down but themselves. Plus, I don't think cheating like that is all that rampant anyway to be worth the trouble of making protection against it. Or is it? I guess I don't really know. Seems harmless enough though.