Hasbro shows their upcoming Star Wars products in magazines and such months in advance. Sometimes they've been known to show prototypes of figures to generate buzz or even to enlighten the consumer on the process they go through to create the figures. Of course licensed products are more protected through the license owner so it would be really tough for a LEGO competitor to have a leg to stand on if they did copy one of those sets.
There are the issues of movie spoilers to take into consideration as well. As in, Disney is not ready for products from their upcoming movies (POTC4 and Cars2) to be shown to the public. They wouldn't want to give away the plot to a movie that really has no plot. Gawd I love popcorn movies.
It really doesn't seem fair that we are punished for looking at the images that show up on the internet while the source seems to go unpunished but maybe we need to remember that these sources are usually quite anonymous. I have no idea who runs 'supercooltoys.com' but TLG does if they supply the site/business directly. Punishing those retailers, no matter how small they are, would be TLG cutting it's nose off to spite it's face; without retailers, how do they get their product to consumers in the most widespread fashion?
Personally, I think they could/should be a bit more proactive and disribute nice hi-res images for us to drool over much earlier than they do. It's not like the sets aren't already in production months in advance of release and there wouldn't be any reason for us to get wind of the prelim set images that they say causes negative reactions.