I know many people tormented even the DPs without a hitch. What those did, I believe, was just phone home to Apple, and this was more for diagnostic than for anti-piracy. The GM is basically the final version (unless, like many have stated, there's a MAJOR bug that cannot possibly be allowed), so I don't believe there will be any issue with the torrented GM copies. That being said, since Lion only costs $30, I see no reason people need to be tormenting it. I see those that torrent it, even at this price, as incredibly irresponsible and inconsiderate.
Some people are just impatient and want to use it now, and then pay later.