Just as a note, cell service at the BM site in general sucks big time regardless of carrier as the local towers have to normally service a population of less than 500, and when you put 70k people out there those few towers in range of the site are quickly overwhelmed. There is a small group trying to implement some boosters/local cell network and to provide better service, but with limitations that won't include outside data streams as needed for Waze.
I didn't go, I just read about this on slashdot. Here is the link to the slashdot posting about the effort.http://mobile.slashdot.org/story/13/08/26/1544207/the-big-hangup-at-burning-man-is-cell-phones
So for the time being unless you've got a sat phone with data, Waze isn't really a good option for Burning Man, you are actually better off with a dedicated GPS device.