Is there any way to prevent these bots?

[Qwertygiy]

They don't post on the forums, they merely comment on just about EVERYONE's user profile with random junk about profiles, pictures, and an email address -- usually it's obviously an attempt at ODing.

Is there a way to "complexify" the commenting system a tiny bit so that whatever program[s] finds the text box / submit page can't find it anymore? Hopefully something "invisible" to players, because I don't think it would be worth it to throw in a CAPTCHA.