Well, not really, but it sure does make it a hell of a lot easier to listen to.
People tend to think of all classical pianists as being as nutty as Glenn Gould, lugging their own pianos with them wherever they go and spending weeks tinkering with its mechanics. They all wear gloves everywhere but on stage, and sit in incredibly low chairs while manifesting symptoms of multiple personality disorder.
The reality is, most pianists are talented people just trying to make a buck who aren't exactly expecting a Lincoln Center quality concert grand waiting for them wherever they go. They're lucky if they're not stuck in front of an upright with exposed hammers, a nearly amputated sustain pedal and a keyboard cover that slices their fingers off if they play too loudly.
See, here's the thing: a talented (or just experienced) pianist is as much a technician as an artist, and is used to playing on all sorts of pianos in all sorts of conditions. Practically anything wrong with a piano, from bad key response to broken pedals to a heavy or tinny sound can be compensated for by altering the way the performer plays. It'll be annoying as hell for the musician, sure, and will necessitate plenty of calming down after the show, but to the audience it won't sound half bad.
There are only two things an accomplished pianist can't adjust for on the fly: bad tuning and sticky keys. Everything else can be worked around. | 
