Out-of-control parents
As I approached the first mile mark of a 5k race, I noticed a young girl (maybe 9 yrs old) running alongside me, crying. I glanced to the side of the course and saw her father running on the sidewalk (not wearing a bib number).
He yelled, "What are you crying about? You've got two more miles to go!"
I wanted to slug him, but I was on a PR pace and didn't want to get arrested.
Parents like that frequent little league, soccer, and other youth sports programs. They aren't often seen at races.
Still, these out-of-control parents can sometimes be a problem for race directors.
They may claim their kids' times are two seconds off or that the course isn't accurate (even when you know it is). They may tell their kids to line-up on the start line and then complain that faster runners knocked them down.
When my kids were little, I'd run alongside them in the kiddie runs. If they wanted to race when they were older (it was always their choice), I made sure they understood the rules.
Deal with parent complaints with the same strength and tact you would use (or should use) with anybody else. Race organizers, not parents, set the rules for the race.