Additionally, the National Park Service has, at some of their facilities,
prohibited cameras and videotape cameras not because of lighting, or
nessecarily a concern for other visitors.  Their justification goes one
step further, and I think with good merit.  The camera holder (video or other)
often looks for the best angle, and in so doing backs/bumps into other objects,
cases, people, barriers etc. causing even greater concern for curators than
timed flash exposures.  In crowded areas this seems to be a justifiable policy!
 
Terry Vidal
UNI Museum