If it’s class that is run typically as a sprint class, then, if the NRRS wants it increase it’s numbers, they should make it an option. That being said, pre-tech that is thorough is essential. I’ve been to NRRS events where the pre-tech has been unsatisfactory, and that can’t happen when brakes are involved.
I don’t know where this $100 figure came up for front brakes.2 rotors, 2 brake rotor hubs, stub axles with caliper mounts, 2 calipers, 2 front wheels hubs, brake lines and a master cylinder. Find all that for $100, and I’ll be impressed. It’s a cost that’s an impediment for sprinters to go road racing.
I’m sorry, I haven’t been racing for 30 years, only 29. There comes a time where the racer has to be accountable for the condition of his/her gear for the safety of that driver and of others. If you’ve no respect for your gear or the speed you’re running, you can have 6 calipers on your kart, and your gear will still fail. In CES, they have front brakes as an option in classes that aren’t exclusively road raced and don’t typically have front brakes, and, because of good pre-tech (at least consistently better than I experienced in NRRS) and respect for the equipment and each other, there has not been a serious injury related to brake failure to my knowledge.
So, if you’re tossing gears or in a lay-down, then keep it manditory. But if you show up in a KPV, no, you shouldn’t.