proven false

Excellent question. I would think it has to do partly with desperate people, wanting answers when they're grieving the loss of loved ones. (I've also been fascinated by people who have lost a loved-one to homicide, and even when the original person convicted had been found not to have been responsible, the family members still often seemingly blindly continue to believe it was the innocent person.)

Apparently, desperation and grieving is just part of the psychology regarding those who believe in psychics, mediums, and the like. The page below offers a discussion on a study done of those who tend to believe over those who do not:

http://news.discovery.com/human/psychology/belief-in-psychics-increases-personal-sense-of-control-130809.htm

Another interesting article:

http://www.theepochtimes.com/n3/1725419-what-kind-of-people-believe-in-psychical-phenomena/

I think the part of human nature that wants to seek answers, opens the door for these "cold readers," and they get tunnel vision; forget the misses, zero in on the "hits," and they cling to it because they just have to believe. Such a pity.

studies have been done but not directly for that. the studies were lead by the atheist community in an attempt to learn why otherwise rationale people would believe in something they can not see, hear, smell, touch, or taste just because somebody said so without any form of evidence.
it turns out our brains are coded to answer why? before how?
first, our brains hate mysteries and loves solutions. endorphin's go off in our brains when we figure something out. so when thunder clapped and we were scared, the only way to rationalize that thunder was to say a "god" was angry. in this case a god would be anything considered to be a higher being of some sort since primitive gods had less and less attributes. we also use correlation as a short cut to try to find a faster solution. if "this" happens before "that" then "this" must have caused "that". the only problem is this is often wrong. your cave wife starts to cry and then it starts raining. the mind first wants to assume that the wife crying must have caused the rain. now the caveman is on a mission to stop the rain by trying to stop his wife from crying. this can be dangerous depending on the level of rational of the caveman.
second, our brains rely on what is the worst case scenario. like Dawkins has said a few times, and i'm paraphrasing, if we were to hear the leaves rustling, we might think it could be the wind or it could be a tiger. the rational way of thinking would be to assume it's just the wind but the survival way of thinking is to think it's a tiger. so it comes down to the what if your wrong argument. if you're wrong about the tiger and it's just the wind, no harm no fowl. but, if you are wrong about the wind and it's a tiger, you're dead.
so when we are given the option follow these rules or go to an eternity of torture the "what if you're wrong" argument comes flying forward. luckily we are past a point of survival and can now relax knowing we can think rationally without getting eaten by tigers. there are probably some grammar errors in this one, sorry but i wrote it fast and didn't go back to proof read it as i do not have time right now.

She isn't.

she has been in direct and indirect ways. when people have used her service they have counted the hits and misses and and have concluded her results are nothing more then the probability of chance through cold reading, a technique used by the ones who openly admit their profession is for entertainment only and not for making money off the sorrows of others. also some of her past employees have come out and spoken out about how she would take advantage of people. indirectly she has been proven false by declining to prove her abilities under reasonable conditions. or in simpler terms, she has made a claim and that claim requires evidence. until she can prove her "abilities" under reasonable conditions then she is to be assumed false, a fake, a charlatan.

how does a rapist or murderer or child abuser or tax collector...