Yeah, it's not a sure-shot thing to get this trojan. You have to make it happen.
Of course, as we all know, there'll be tons of people (who'll I'll refrain from labeling at this time) who will see a new attachment in an email one day and say "Wonder what this is, I should click on it to find out," and bam....they're screaming "Look what Windows did to me! This isn't my fault! Why did this happen!?! I did nawthyng!"
Idiots.
I seriously believe some people should be banned from using any computers whatsoever. You should have to have a license to operate a computer, like operating a car.