With regard to why the screen shot is not OK, is something you will have to ask BA.
I was just confirming that we can't accept them but I an afraid I don't know the reason.
There is a thread about the BA APP and a BA technical representative monitors it, so you could post your question on there and he may be able to answer it for you.
As I have mentioned before, there is no need for crew to touch the screen and this should not be happening. BA have been reminding crew of this, so hopefully you won't get crew trying to do this too often from now on.