Another tricky component of the "rest" or written pause is the tendency
of pianists (and I include myself) to sustain notes longer than necessary,
usually with the help of the piano's sustain pedal (you know, the one on
the right!).  Too much pedal--or perhaps any pedal at all--can obliterate
a rest.

Where a composer like J. S. Bach is concerned, this of course is a no no.
Contrapuntal lines tend to become obscured.  Glenn Gould is one pianist
who, notwithstanding the fact that he undoubtedly hummed through rests,
certainly did not commit the faux pas of over-pedaling.

John Grant
http://artists.mp3s.com/artists/42/john_lewis_grant.html