When I started with player pianos, I was surprised that none of them
had a spill (safety) valve on the reservoir as did the reed organs with
which I had become familiar.  That aside, I have observed that pneumatic
players are gentler on piano actions than human fingers and (up to a
point) fists.  Ivory keytops are, of course, excluded; it seems that
unruly children like to whack them with silverware and other hard
objects.

A while back I took in a better-than-average grade upright player piano
with cedar hammer shanks in the extreme treble.  I'd seen this in other
instruments as if this type of construction was believed to have some
kind of advantage.  All I know is that many of the finest pianos were
built with maple shanks all the way.

Well, this particular piano had more than the usual number of chipped
and pulled-up ivories, along with a few of the cedar hammer shanks
broken.  The cedar wood had become dry, weak and brittle, but none of
the maple action parts were so affected.

Jeffrey Wood