Does ritual impurity transfer to the hair, hand, or bedding if its exact location is unknown?

"Waswasah" (whispering of Satan/obsessive doubt) is one of the most dangerous diseases, and its cure lies in ignoring it and not paying attention to it. The fundamental principle is purity, and a ruling of impurity transfer is only made with certainty. Therefore, your sleeping on a mattress with an unknown location of impurity does not make your wet hair impure, because the fundamental principle for your hair is purity, and there is no certainty that it touched the impure spot. And if there was a barrier between your hair and the mattress, then it would not become impure, all the more so.