also, why the hell would these clowns put a billboard up in the middle of the desert.
OK first, take a look at the pic. The billboard colors are very very sharp. They aren't in line with the rest of the colors in the photo. It also looks to me like the guy is looking too far to the left of the billboard to be looking at it, which might lead one to believe the billboard was added into the photo later.
FWIW (probably nothing)