Perhaps that would work, but taking that idea one step further: I doubt that there's anything you could do to them legally, because the evidence of a similar writing style most likely wouldn't hold up in court. IANAL but I think the least you need to prosecute someone for their actions on the internet is an IP and a statement from the ISP that the IP was assigned to this users account at that very moment.

And then again I am unsure if simply visiting and contributing to such a forum could get you in any trouble, legally.