If the Defending Pokémon has a status change (like Poison) but an attack requires you to flip to see if the same condition is afflicted, do you still have to flip? (Eg - Weedle's Poison Sting reads "Flip a coin. If heads, the Defending Pokémon is Poisoned.")
Yes, you have to though I can understand why you would consider it redundant.
Source: WotC Chat (2000-05-11)