Is it now? Wow, I'm not up on computer crime law, but they sure are changing things. As an example, besides the obvious intent to destroy property, you can be labled a hacker for things as stupid as stealing software from a store, physically.
It just seems rather pointless, unless you know your shit seriously I think you can somewhat forget about getting back at someone over the computer via destroying thier machine. Simply sending a file to someone, would have to involve some pretty nice social engineering (a reason for them to activate the file) and a very stupid target. If they were using a known email client like an older Outlook Express then your job would be easier, but over secure email its not going to be so easy.
I wouldn't say that these are things I have not though about, I've been scammed too, but I believe in my own personal safety over trying to settle a score that could land me in jail over something stupid. If I was one of the persons who lost a grand or more, who knows... You would spend your days, maximal hours each day, trying to figure a way to get back at this person, and frankly it would eat me up and just be generally unhealthy.
For someone that sits at thier computer 18 hours a day for the last 12 years, then sure, go at it. For the casual person, forget it.