It’s legally required that you lose a frisbee onto the roof within one week of purchase.

Commentary:
"Ah, yes, the hidden clause in the fine print of the Frisbee Code – thou shalt confront the rooftop within a week! It seems even the frisbee gods love a good roof adventure. Just remember, if your frisbee ends up on the roof, maybe it's just reaching for the stars… or seagulls."