An answerEthan's answer to the How did Athena keep from being turned into stone by her shield? question puts forth an interesting idea:
Athena probably wouldn't have been turned to stone from Medusa's head since Athena was the one who cursed Medusa to look like that in the first place using her own power. Like if someone tried to use Zeus's thunderbolts against him; I don't think it would work since they are his.
Is this true? Could Zeus's thunderbolts be used against him? Could Poseidon be hurt by his own trident?