The demo is try-before-you-buy and even if the game has serious bugs and the demo doesn't, that doesn't mean its not going to be a good game eventually. There's no reason to play the demo, say, "Well the full version may have serious bugs so I should download it and check it out," and then warez it and never buy it. That's just unacceptable.
I agree with the last point.
Though I have some games, or better had, that I somehow never bought, was years ago, and most bother me not (mostly stuff we played on lan partys mp, and never again), only sc and hl, those two really bother me, I must buy them sometime (have cs retail though), had them even in my hands and wanted to buy them ... but well than my gf told me how very much she would like to have .... and I run out of money ... I know lame excuse, but sometimes it just happen. Good that it happens now very rare (actually in the last year not a single time), as I have more money to spend and buying a game does not hurt my wallet for the next 2-3 months
what I really do not like are ppl that just warez cause they could, if someone simply has a limited budget I have no problem with that, as long has he still buys aswell, what these days most ppl I know do.
btw what really makes me wonder is, how many ppl are strikly against pay to play and aswell strikly against warez. Pay to play is something I have bother somehow much much less, than spending money for a game that I play 2 days and never again. (like my populus 3 and black and white originals)