Epic's Mark Rein posted on the official Gears of War forum that despite a recent image seen on the British version of Xbox.com, there are no plans to release a demo for Gears of War prior to the game hitting retail shelves.
The post from Rein:
"Just saw the dog tag image with the "Microsoft points". It just isn't true. There is no demo coming out before the game ships and I have no idea if we'll do one after the game ships or not. Right now there are no plans to do one as I said earlier in this thread. I have asked Microsoft to take that image down."
If Xbox 360 owners see a demo, it will not be until after the game is released. In the fickle gaming world, demos can be a double edge sword. If a company puts one out and the gameplay (while usually not indicative of the entire game) is mediocre, then it could hurt game sales and word of mouth. If a company doesn't put a demo out for a high profile game before release, then speculation tends to run rampant that the game is mediocre or not meeting the hype.
Which will it be? We wont know until Emergence Day....