First off the the people making jokes in the beginning of this thread lack a heart and a brain. Someone's death isn't funny. My thoughts go our to his family.
I have messed with broken electronics since I was a kid. Fixed some, broke others. I also loved reading so I had a few books teaching me what was safe (Don't touch that, wear gloves, safety glasses, etc). Now, if I never learned that, I would have been at a greater risk of injury or even worse. You can take apart most things and be 100% safe if you unplug it.
Mistakes happen, this guy could have been very knowledgeable, and just managed to brush the wrong capacitor. Or he just wanted to know how it works and didn't think an "unplugged" computer could be dangerous. Discharging everything before hand is helpful if you have the option. My #1 rule was don't even look at CRTs, way to many "bad" things.
Another thing, I don't think he was just swapping "complete" components. A PSU that you buy on Newegg isn't going to kill you (without doing something REALLY wrong). Now if you open it up then it gets dangerous. Most people that work on a computer as a hobbyist are just pulling plugs. If you are working with a soldering iron and resistor jumping it's much more important to know what you're doing for both the components and your safety.
