Dave
I agree. Things happen and everyone can miss a job once and awhile I'm sure the owners go through this with all their staff. Its a no brainer that they need to be notified and if they weren't then the pay cut was justified and perhaps a get even move for being disrespected. What job can you miss and not notify the higher ups? An experienced musician should know that from day one.
Musically I'm sure the fill in singer did a great job and no one really cared except the owner who probably felt blindsided. That place is jammed ever night no matter what entertainment they offer. Like so many other restaurant gigs we're just icing on the cake.