What is your opinion of the "Poltergeist" Curse?

Okay, I was aware for a long time that Heather O'Rourke from the Poltergeist movies died before Poltergeist III was even released. But I just read that several other cast members from the Poltergeist series died around the same time that the Poltergeist movies were coming out, including Dominique Dunne, who played the oldest sister in the first Poltergeist. She was strangled by her boyfriend in 1982, the same year that Poltergeist was released. Weird! So do you think that all of this was just a coincidence or that there really was a curse?