In the flashback scene where Jen and Lo are in the desert, they come to a sandy hill-like area (can't miss it, it's like a hill and it's all sand, not just dry land like other scenes) during Jen's pursual.

Apparently, the desert is abandoned -- when the camera pans to Lo, that's the feeling you get, only the two of them. Now the camera pans to Jen and you see many footprints behind her! Kind of ruins the abandoned feeling, right?

This was pointed out in the CTHD commentary on the DVD as well... apparently, the camera crew had stepped there earlier and no one had bothered to clear their footprints.