Yes, the perception filters are popping up all over the place; it's like the new lazy explanation on top of the sonic screwdriver. There was one around the door in The Eleventh Hour, there was mention of it in Time of Angels/Flesh and Stone (low-level perception filter or maybe we're just thick), the vampire ep had kind of the same idea of perception filters in the cloaking device that Rosanna and Federico used, I keep thinking there was something else too but at any rate, yeah, enough with the perception filters. It's lazy writing.