premature folding

hey,
I was playing a freeroll today and even in other games i see it too,people folding even though they can check !?
I.E when they're the BB they can check no one raised or anything, dont they want a 'free' card?
whats the deal here, is there a secret masterplan behind this ? [img]/images/graemlins/laugh.gif[/img]
Cause i dont see it...

thanks

-peace