Yes, photography and moving around in the hall should be banned at any un-amplified concerts and free mint candies should be given to all that intend to cough - many times I think it is nervousness related - people just can't keep silent for so long.
I have never ever coughed at concerts in my life... if I have serious cold I usually don't go out anyway... and I can clear my throat during the applause if I REALLY have to. Sometimes I prefer listening on a good hi-fi system, because audience can be too annoying and distracting.
Photographers walking around, the noise of shutters in reverberant spaces and un-amplified music just don't mix well...
Actually I must say that I never saw any photographer during serious classical concerts - not some school production - there must already be such agreement here. But there was one un-amplified jazzy-classical concert (only a duet
of violin and viola) in one acoustically very live baroque salon and the photographers were ruining it... I hated their lack of sensitivity sooooo much... they just wouldn't stop shooting even when the people started moaning in protest... idiots.