Anthony Tommasini writes in the IHT on the trend to allow concert pianists to play from music, instead of playing recital solos and concertos from memory.  A good thing too!  While playing from memory is an impressive feat to watch, it certainly takes additional  practice effort to achieve:  I would rather good performers played more different music than that they played a smaller collection from memory.
I saw Angela Hewitt play the Bach 48 from memory in Cottonopolis a few years ago.   At the first concert, a woman  in the front row was reading from a miniature score.  After the first few preludes and fugues, Ms Hewitt quietly asked the woman to put her score away, as the page turning was distracting.  My guess is that the page-breaks were happening at places other than where Ms Hewitt had memorized.   (As an aside, her performance was very good but her interpretations undermined by rubato.  I prefer my Bach straight, not with flavoured mixers.)
Note:  The hands shown are those of Szabo Daniel.