So then the issue appears to be (again) clarity in the manuals. Suprise, surprise.
How about someone directly ask the big boss then? Get it on paper then no more worrying about it and having to cover one's... rear end
I imagine IF it was a real issue, the tons of images of pax in our flight decks (on ground) doing the rounds of Ninjagram, Twipper and BookFace would have got security dept's interest long ago... they do look at that stuff on a regular basis (someone does, anyway) and passes on anything relevant. There is a video which is a bit 'famous' that they could have asked to be removed if they wanted to, they have not so would assume they do not think it any risk to be there. Same goes for all the post-flight
PR pics...
So- anyone can tell us for 100% sure it is 'banned'?