No it isn't. For example, I don't play games at all, but I pirated Left 4 Dead because everyone said it was so good. If it wasn't free, I wouldn't have gone out and bought it. A lost sale? Nope.
Haha, I pirated that as well. Then I realized that the PC version SUCKED on my crappy ass computer (PS1 emulation works flawlessly though) so I went and bought it for the 360. Lost sale from pirating? No, a gained sale!!!!
Although that hardly ever happens in the real world of warez, lawls.