I knew several people who not only went in thinking it was real, but also came out thinking it was real. You might say I hang out with stupid people, but I honestly believe they're a pretty good cross section of America.
And as far as it being about a witch, do you realize how many religious folks get upset about things like Harry Potter because it involves 'witchcraft'? Obviously those people believe witches are real and dangerous.
On July 11, 1999, when Ebert first wrote about Blair Witch from Sundance, he said, "As I was walking out of the Sundance screening at midnight, people assured me it was a "real" documentary. When I disagreed, they said they'd "heard" it was, or remembered reading in a paper about the disappearance of the three documentarians. Thus do urban legends bloom; everybody knows a "friend" who is the source of the story."
Seriously, people are really stupid. You'd think after seeing the film they'd know, but they don't.
You know that urban legend about a woman in an atlantic city casino elevator with a big bucket of chips and two black men get on the elevator with a dog, and one says "sit", and the woman, apparently a racist lunatic dives on the floor. And the next day she receives flowers in her room with a card signed, "thanks for the best laugh we've had in years", signed Eddie Murphy and Michael Jordan!
A guy I used to work with(this is a middle aged man, college graduate, aeronautics engineer), he swore up and down that this story is true and it happened to his nephew, but the man in the elevator was actually Lionel Ritchie. People are so stupid. The funniest thing is when he tells the story, he apparently has no idea how racist and bigoted it makes him look by relating the story as if his nephew's reaction to a black man on an elevator was somehow reasonable. Also, Lionel Ritchie? Really? He was scared and intimidated by Lionel Ritchie?
Anyway, so yeah, Lionel Ritchie is the Blair Witch. People are so stupid.