S
Styrofoam
Visionary
Silver Level
You answered you own question. Because it's a freeroll, and there is no financial punishment, just a waste of time. You cannot bluff anyone in chess, so not the best analogy.
To many, IMHO, winning is all about earning money, and the ends justify the means. Although bluffing and aggression depending on position, reading opponents, etc is a respected skill, freerolls are different animal, and no one is willing to invest the time to play the 'right way', or play as though is was real money. I don't know about NLHE, but of the freerools I've played at Poker Stars, where the top 88 might qualify for same round 2 ticket, many past the bubble have pride in their play of the game, and play very well to the bitter end.
true that you can't bluff anyone in chess... but you can make a move contrary to what would seem like logic. IE: Sacrificing your queen for a long term positional advantage. While its not exactly a true BLUFF, it could be equated to such in chess.