Learn something new every day…
Oh, also, I would like to point out that when movies truly suck beyond sucking, they don’t screen them at all for critics.
Or they wait until the night before release, it seems.
As others have said, (a) it’s completely normal for studios to require critics to agree not to publish their reviews until the day of the film’s release, and (b) the big red flag of a movie’s quality is no advance critic screenings at all.
No conclusions whatever can be drawn about the quality of this film from the practice mentioned in the OP.
Some critics “self-embargo” because it’s the decent thing to do. Ebert usually releases his reviews only on the day the movie opens in Chicago. Film festival reviews of movies that later are released nationally, etc., can cause a conflict with this policy, but he does what he can.
Note that Cruise and Spielberg are control freaks and control freaks just Do Stuff to other people for no good reason other than to demonstrate their control. This might be one of them.
But I do suspect a stinker.
Maybe this version of “War of the Worlds” will have a surprise ending unlike the previous versions.
To quote another thread - the favorite, all-time deus ex machina - It was all a dream !!!
Well…the point of my post was that the ending is so well known and copied that even if you don’t already know the ending, five minutes into the movie you’ll know the ending.
Still, apologies. And thank you for despoling it. 
What does the studio care? How is that taking money from them?
Along with seeing a film the press gets a press kit. Images from the film that have not been released. Frequently a specific media outlet may get a unique set.
So if some paper publishes this week “Exclusive Photos of WotWs Tripods!” then that spoils somethingk they have been holding back and that papaer does sell extra copies. It doesn’t so much take from the studio, but it is unfair. So all of the media is given a date they can publish. That date is the day the film opens. The studio cares so all the media gets an equal shot. Plus, having the title of your movie in a headline the day it opens is a good thing.
It’s not like it is possible to screen the movie for every critic at the same time and then say, OK who ever publishes first gets the scoop. They would be writing their reviews on blackberrys in the theatre straight to the net.
Just to nitpick a little. The spoiler was wrong, it wasn’t
death by virus, it was death by bacteria.
Jurassic Park’s publicity was similarly very carefully controlled - only certain very limited images of the dinosaurs (only two shots from the T-Rex scene, and I think some of the Brachiosaur reveal) were allowed to be shown until the day of release, and in fact probably a long time beyond the release date, so that the spectacle was still protected.
Unusually, the “Making Of” documentary for Jurassic wasn’t made until a year afterward, for the same reason - to protect the secrets and surprises. So this is not an unprecedented move.
Indeed, perhaps the rumours of it being a bad movie are deliberate anti-publicity to keep an element of surprise still. Kind of make it have a sleeper hit reaction, even though it still has all the elements of being a blockbuster success anyway. I dunno, I’m just making stuff up now.
It’s a trap!
