Categories are meant to divide skill levels. Open category races are inherently dangerous, due to the varying skill levels. Qualifying, heats, or rounds all achieve the same purpose.

I don't see why most people assume grass-roots racing will automatically result in some version of internationally-sanctioned, regulated, and soul-sucking racing. The track racing portion of this year's West Side Invite was OBRA-sanctioned, and all the riders didn't turn into "spandos". Hell, some messengers even competed in the Rapha Roller Races. Most of these unsanctioned races already have sponsors--they're only one step from collecting permits and waivers--especially if they're collecting money to run the event.

Racing is a balance of risk versus reward. Keep the rubber side down and the shiny side up.