In answer to your first question… assuming Lemmy represents all of Canada… all of them?
For the second, failure to appear is contempt of court. In practice, failure to appear for jury selection usually just results in your name going in the next pool, as long as you have a reasonable excuse. Failure to appear in court once selected though… that’s serious. Courts can still be very lenient if the juror appears to have made a best effort to appear, but just blowing it off can result in fines or jail time at the discretion of the court.