There was a whole thread about picking up the wrong horn. It might have been on TH though. I played at the same church Christmas eve and day. I had no idea what we were playing so I brought a B-flat and a C and a Picc. After the first job I saw I only needed the B-flat and came the next day with one horn in a gig bag. The guy playing second had the same idea. When he pulled out his horn, there was no first valve slide. He had to drive home and get it. and missed 1/2 of the first service. I was out of the church before him after the job but, I don't think he gave back any money. We're human and that's the kind of stuff that happens. Live performance. Good and bad, that's what makes it better.