I've helped with the black-line-painting club. Two years ago the driver compalined that we were doing our jobs too well. We were asked/told to hold the orange cones up so the driver could sight on the line of 'em, and when the truck approached our position -- we were to jump aside so we didn't get hit. The driver commented to Cris Shearer, who was riding with him, that we were waiting too long to jump aside -- that he was afraid he was going to hit us and would involuntarily swerve a little each time. After it was all done we were told that we could move sooner next time around. . .
Last year Nancy helped with the line. Maybe the driver was busy checking out her tattoos or something instead of concentrating on the straightness of his driving.
But -- you're not supposed to be on the line when going down the course -- you're supposed to be between the lines, and too busy to notice that the line isn't arrow-straight.