There's never much of a risk involved when registering a domain name, but you'll notice that movie studios still only tend to do it with good reason.
Consider Sony Pictures, for example. A couple of months back, Fusible caught them registering domain names around the word Skyfall, some of them explicitly mentioning James Bond, and so it was we first found out the name of 007's next adventure.
This week, they've locked down domains associated with Insidious 2, strongly suggesting that a sequel to the kinda-sorta haunted house movie will be announced before long.
The first film, which I enjoyed considerably more than any of James Wan's other pictures, has been hugely profitable, returning US box office of over $54 million against a spend of $1.5 million. Sony should have gone ahead and registered Insidious 3 domains while they were at it.
Incidentally, MarkMonitor, the domain registration company used to execute these acquisitions for Sony, recently also nabbed a series of Pinocchio: The Movie domains, very possibly associated with the Gris Grimly stop-motion Pinocchio film that's in production now; and some more to do with something called The Gold Mist Movie too. I'd guess that last one refers in some way to Gold Mist Avenue in Vegas.