Transformers 3 Extras Casting via Craiglist? (Updated)

Update: It appears the Craigslist ads are not real, at least not affiliated with Dreamworks or Transformers 3. Prompted by user in comments, I called the number and reached an operator who read from a script, tried to get contact information and directed me to sign up to ActorsOnSet.com website for a "one time fee" of $98.90. If you have to pay someone to find you a job while they are supposedly getting paid to fill jobs, that strikes like the classic definition of a scam. Rather then pull the post or the ad below, leaving it up in case people Google the phone number and can get additional information they need to decide for themselves on what to do.

If going by the listings on LA Craigslist, it appears that Transformers 3 production has begun to look for extras for filming. No date is specified on when filming may begin. Extras are those people you see walking and talking in the background of scenes that are seen but rarely ever heard.

Here is an example ad:

It's Amazing,Spielberg is back to work again.

Release Date: July 1, 2011
Studio: DreamWorks Pictures (Paramount)
Director: Michael Bay
Screenwriter: Ehren Kruger
Starring: Shia LaBeouf, Megan Fox, Tyrese Gibson
Genre: Action, Adventure, Sci-Fi
Plot Summary: Bay and Spielberg are working on the plot for the next chapter in the Transformers saga due in theaters 2011

Pre Casting Starting, ***Contact Casting 1-877-464-9526*** For Background Scene work. Extras Are needed. No Experience Req. Union and Non-Union OK.

Location: Los Angeles
Compensation: $100-$300 a day
This is a part-time job.
Principals only. Recruiters, please don't contact this job poster.
Phone calls about this job are ok.
Please do not contact job poster about other services, products or commercial interests.

I do not know anything about how extra casting works so no idea if using Craigslist is the norm or not. A quick Google on the provided phone number doesn't provide any clues on legitimacy one way or the other. If you are in the LA area and curious I just recommend caution. Remember the goal is to hire and pay you for your time so if they ask for money it is probably a scam.