Its very true, the downside is that it is hard to inform someone of something like this. Many people take things personal especially mini moms and dads. But he hit the nail on the head when he stated I would rather offend a parent than watch a kid get killed. Personally I think split practices can avoid this completely. You should never ever have 50's and 65's on the track with big bikes and 85's probably should not either. There are exceptions of course like the 85 kids who scrub so hard they can pass me in mid-air over a triple. Big bikes can be a hazard too, I am a big advocate in running practices for 1) pee-wees, 2)65s, 3)85's, 4)C riders and 5)B/A riders. I know this can cost people some track time but I prefer safe to sorry. Having a pee-wee track is a huge plus because it eases congestion, you can run pee-wees, trail bikes and even 65's. Rules don't have to be concrete either, you can make exceptions to let certain 65's run with 85's and certain 85's to run with the big bikes. I am a C rider but I often practice with B riders because they typically don't want to kill you or to "practice block passes".