Benefits of freerolls
I agree with some of the previous posters that some people equate freerolls with play chips and throw all-ins on a whim. But like some of the others said, freerolls are free money - you can build your stake and get into cash buy-in games without risking money of your own. Try out the play at various sites. I have found some sites to be 'free money' sites because so many of the players are beginners and don't have any idea of how to play. On others, play has gotten tighter as players learn. One site, that I have a little money on, has 3-person 10 plus 1 cent winner-take-all tourneys all morning until about noon ET. As soon as one tourney ends, another is available. It is definitely free money, as you only have to outplay 2 people to add 30 cents to your bankroll.
My advice is to play as tightly as you know how, regardless of how the other players are playing. If they are going all in with junk, fold to all-ins unless you already have a boss made hand like a straight flush, full house, or 4 of a kind. Fold to most all-ins before the flop.