While everyone here has some good points.. And maybe its the Mom in me but while my pack is required to have boy involvement in building their cars (sanding, painting, decorating) I much prefer the adults to do all of the cutting for safety issues. And as much as I dislike the idea of the "pre-cut" car bodies (I still require them to go buy the tires and axles from BSA) you can purchase at places like Hobby Lobby I do not disallow them for the simple fact that many of our boys do not have a parent or the equipment to cut the car out for them. Yes the car might be pre-cut but the boy still gas to sand, paint, decorate, make sure it meets all weight,height requirements, ect.
We had some issues at our Blue and Gold/Pinewood Derby last yr (parents arguing among themselves) and as I stressed at the parent meeting the following week to address those issues.. It was not about the parents or what the parents felt was fair or unfair.. I was there to make it a special night for the boys. That although I do not know every boys home life I do know that for many boys this was the one thing out of the year that was special to them as they may not get that special recognition at home like celebrating a birthday or other holidays that many of us try to make special days for our children. It is for them and about them. So what if one boy was 10 mins late for registration deadline. Its not like an 8 yr old can drive himself to the banquet hall.