“Those sending computer viruses to this email will have their ip addresses forwarded to the proper law enforcement officials.”

Right. Most people whose computers are infected with a computer virus are probably unaware that it is infected. How many people think, “Hey, let me infect my computer with a virus and let it send out infected emails!”? Hopefully, not many.

By that logic:

If your computer is used to commit a crime, then you are the one held accountable. So if your computer attempts to hack into other computers because it is infected with a virus, then you should be punished.