Ad Hoc Excuse?

I seen today a older forum post by a skeptic who says that its an ad hoc excuse to say that patients who have had a out of body experience would not be able to see the signs from near the ceiling because there attention would be on their body and the people around them. He also says that if we don't get the results we want (else believers) from the aware study we will just make up endless ad hoc excuses. However, me along with others see it as a legitimate problem one that has been taken into account.