So if you sneak into an evil necromancer's tower and copy all his spells, are you then a necromancy pirate? Man, D&D so does not take into account the black market for pirated spellbooks.
I voted pirated, liked it, bought it. I don't like buying something unless I can look at it and since there is no hobby store anywhere near me, getting a look at the pdf was my only option. Personally I don't find it unethical to download something to take a look at it... Same goes for mp3s. I download it, and if I like it buy it, if not, it goes in the trash.