Do you mean who has mounted a camera obscuring the view?
Look at the vid WP has embedded. The device is there at the start of the vid, seems to be absent from other bits, but is certainly there when flying at min 2.30. Right in the middle of the coaming and taking up a big chunk of the view. Given that a conflicting aircraft will have no change in the relative bearing, he's unlikely to see an almost head-on conflictor. By all means mount a camera internally or on one's head as WP has done but please not where it obscures the view outside.
We have a responsibility to each other to SEE and be seen.