Most the it is people who feel like they got cheated in the ring, sounds like you did not have a complaint against the judging just the sale price your child received, is that correct?
We run 200 hogs, 100 lambs, 40 beef, 20 goats and the small animal pens. I have seen the 155 hog go through the sale for more than the grand champion ( parents writing off some college tuition money) I have seen the average for steers run around 3 a pound and drop to 1.50 for a few head in the middle of the sale it happens.
If your son placed well and was either close to a breaking even or made a little money he should be happy and move on. In my day way back when we averaged $1.10, a $1.25 was awesome. Heck I may have made $300.00 that year. If you are in it for the money I suggest your son get a job, if you break down the hours to dollars, 2 hours a day, 180 days, 1000 profit ,they make 2.77 an hour.
If they are in it for the love of animals, the learning experience, then I suggest you step back take a deep breath, and think about what you need to do next year to help your son with buyers.