Thanks for all the postings. I probably should admit that I was a little too bitchy about this performance.
As for the concept -- which several posters stated -- that most of the audience did not notice anything out of order with the performance, so doubtless that makes the performance satisfactory . . . well, come on! It's either competent or it is not. As for the acumen of the average citizen . . . well, if any of you have played for people in your home, such as family, you will discern that many of them will be respectful and courteous, and listen carefully, but have no idea what they are hearing. Moreso with classical selections. The fact that miscues or wrong chords, or flaws in timing, went right over their heads . . . does that make the performance okay?
It is partly about what music that average people know, also. This is not to be snobbish. But many persons like what might be called better-quality popular music. Now if the pianist played "Bridge Over Troubled Waters" with an equal number of mistakes, half the wedding guests might have frowned and looked at each other. But a high percentage of today's Americans really don't understand classical piano music very well.
And yes, this man did play quite a few other selections far better, and in quite a satisfactory manner. What was bad about his miscues in the Canon, it was the entry march, and arguably the most intent moment of the service.
Another thought occurs to me. The Canon in D is available in many arrangements for piano. I myself have at least five of them. Possibly this pianist selected one of the most difficult of them. If caught by surprise, he might have been wise to have selected an "advanced" version, but one somewhat less challenging.
Thanks, and mea culpa, I have probably been something of a "cold dude" about this. I will go off and do suitable penance.