They don't check whether or not your truck is 4wd or not. Basically its on you if you F*ck up your truck. I have been out there a few times in my 4x2 and have done just fine. Take a look at some footage of my truck back in Nov.
http://youtreadtube.com/item/5BKXQ7GBDHDWCS65 I do recommend that if you decide to go bring someone that can pull you out!!!