The lure of the sheer amount of money being offered as prizes and the promise that all the winning entries will "get published" (as someone pointed out in the comments to Victoria Strauss's post, that language alone is iffy - it's usually "be published" when the event of publication is discussed by industry professionals) might be more than enough to entice young and innocent aspiring writers who don't know how to check for these scams into the fold. Rule of thumb - if it purports to be sponsored by a big organization, check on the organization's website first. THAT is where a contest (if a contest there was) would be advertised... not on Craigslist.
Writer Beware.
This has been a public service announcement.