In all of these cases, the WORST outcome is that you don't make any money.
The worst case is it costs them money, due to transaction fees. The argument isn't against piracy. It's actually preferable to them if you pirate rather than pay one cent, which is what tcaz was saying.
Although, since you did bring it up, I've never been particularly sold on the argument that people who pirate often bring in more customers by telling people how awesome it is. In my experience it's usually a lot more like
Person A: Yeah, this game is pretty awesome
Person B: Oh really? Sounds interesting
Person A: Yeah, I can give you the .iso if you want
It has pretty much an equal chance of bringing in new customers as it does dissuading someone from buying just because their friend can easily give them the game.
What has the biggest impact is convenience and extra features, really. Just as it's easy and convenient for me to grab an .iso and a crack from someone's external drive or dropbox, it's easy for me to just buy a game from Steam, which has numerous benefits if I do (being able to download it anywhere, the whole Steam community thing, etc.). And sales obviously make it much easier to impulse-buy
Basically I feel that pirates bringing in additional consumers is not generally something that happens to any noticeable degree. I'm sure there are stories, but I think it's pretty rare that pirates are actually beneficial. They're mostly just neutral.
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Ginhyun
http://i.imgur.com/15vH5.gif